Legato Networker 7.1 Cross-Platform Performance Tuning Guide

Legato Networker 7.1 Cross-Platform Performance Tuning Guide
NetWorker
™
Cross-Platform Version
Performance Tuning Guide
© 2003, LEGATO Systems, Inc. All rights reserved. This product may be covered by one or more of the following patents: U.S.
5,359,713; 5,519,853; 5,649,152; 5,799,141; 5,812,748; 5,835,953; 5,978,565; 6,073,222; 6,085,298; 6,145,089; 6,308,283; 6,324,654; 6,338,126.
Other U.S. and international patents pending.
Legato NetWorker Performance Tuning Guide
July 2003
22a-1950-03
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Contents
Preface ......................................................................................................... 11.
Audience.......................................................................................................................... 11.
Product Documentation ................................................................................................... 11.
Conventions..................................................................................................................... 12.
Information and Services................................................................................................. 13.
General Information .................................................................................................. 13.
Technical Support ..................................................................................................... 13.
Licensing and Registration........................................................................................ 14.
Customer Feedback ........................................................................................................ 14.
Chapter 1: NetWorker Features ................................................................. 15.
Introduction to NetWorker Editions.................................................................................. 15.
Overview of Hardware and Software Performance ......................................................... 17.
Chapter 2: NetWorker Configuration......................................................... 19.
NetWorker Software Services and Programs.................................................................. 19.
Services and Programs on the NetWorker Server ............................................. 19.
The nsrd Service .......................................................................................... 20.
Other Services and Programs...................................................................... 20.
Services and Programs on the NetWorker Client ............................................... 21.
How the NetWorker Software Backs Up Data........................................................... 21.
The savegrp Program ......................................................................................... 21.
The nsrmmd Service .......................................................................................... 22.
How the NetWorker Server Recovers Data .............................................................. 24.
NetWorker Configurations ............................................................................................... 25.
Immediate Save and Recovery ................................................................................. 26.
Local Backup and Recovery of a Client .................................................................... 26.
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Performance Tuning Guide
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Contents
Backup and Recovery of Remote Client....................................................................27.
Backup and Recovery to a Storage Node .................................................................28.
Local Backup to a Silo ...............................................................................................28.
During Backup.....................................................................................................29.
During Recovery .................................................................................................29.
Chapter 3: Testing and Tuning Basics ......................................................31.
Overview of Performance Testing and Tuning.................................................................32.
Server Hardware ..............................................................................................................33.
Physical Disks ...........................................................................................................33.
Disk Read Speed Testing Methods.....................................................................33.
Options Valid for All Modes of uasm ...................................................................35.
Options for Save Mode .......................................................................................36.
Options for Recover Mode ..................................................................................37.
The -i Option .................................................................................................38.
Disk Performance Tuning Methods.....................................................................38.
Memory and CPU Usage...........................................................................................39.
Memory Usage....................................................................................................39.
CPU Usage .........................................................................................................39.
Server Input/Output ...................................................................................................40.
Input/Output Backplane.......................................................................................40.
SCSI I/O Bandwidth ...........................................................................................40.
NetWorker Settings ..........................................................................................................41.
Server Parallelism .....................................................................................................41.
Client Parallelism .......................................................................................................41.
Multiplexing................................................................................................................41.
Modifying Settings for Performance Tuning ..............................................................42.
Parallelism and Target Sessions Attribute Settings ............................................42.
Workload Balance ...............................................................................................43.
Multiplexing .........................................................................................................43.
Backups Across a NetWork ................................................................................44.
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Legato NetWorker
Performance Tuning Guide
Contents
Backup Devices............................................................................................................... 44.
Device Write Performance Tuning Methods ............................................................. 44.
Testing Tape Device Performance without Running NetWorker ........................ 45.
How to Determine Tape Device Performance.............................................. 45.
Limitations .................................................................................................... 47.
How to Test Device Performance with bigasm ................................................... 48.
Device Performance Tuning Methods....................................................................... 48.
Input/Output Transfer Rate ................................................................................. 48.
Built-In Compression .......................................................................................... 49.
Drive Streaming .................................................................................................. 49.
Device Load Balancing ....................................................................................... 49.
File Type Device and Staging.......................................................................................... 49.
Configuration of File Type and adv_file Devices....................................................... 50.
Without Save Set Staging................................................................................... 50.
With Save Set Staging........................................................................................ 51.
Network Hardware........................................................................................................... 51.
How to Tune NetWork Hardware Performance......................................................... 52.
Chapter 4: Testing and Tuning on UNIX and Linux ................................. 53.
Physical Disks ................................................................................................................. 54.
Benchmark Evaluation .............................................................................................. 54.
How to Test the Read Speed of a Single Disk .......................................................... 55.
How to Test the Read Speed of Several Disks ......................................................... 55.
How to Test the Read Speed of a Single Disk While Running the NetWorker
Software .................................................................................................................... 56.
How to Test the Read Speed of Several Disks While Running the NetWorker
Software .................................................................................................................... 56.
Devices............................................................................................................................ 57.
Benchmark Evaluation .............................................................................................. 58.
How to Test the Write Speed of a Single Tape Drive................................................ 58.
How to Test the Write Speed of Several Tape Drives............................................... 58.
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Performance Tuning Guide
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Contents
How to Test the Write Speed of a Single Drive while Running the NetWorker
Software ....................................................................................................................59.
How to Test the Write Speed of Several Drives While Running the NetWorker
Software ....................................................................................................................60.
Using the System Activity Reporter..................................................................................60.
How to Monitor Buffer Activity ...................................................................................60.
How to Monitor Block Device Activity ........................................................................61.
How to Test CPU Utilization ......................................................................................62.
Recoveries .......................................................................................................................63.
How to Perform Multiple, Simultaneous Recoveries .................................................63.
Chapter 5: Testing and Tuning on Windows.............................................65.
Windows Performance Monitor ........................................................................................65.
How to Start the Windows NT Performance Monitor .................................................66.
How to Start the Windows 2000 Performance Monitor..............................................67.
Testing a NetWorker Server from Another Computer ...............................................68.
How to Test a NetWorker Server from Another Windows NT Computer ............68.
How to Test a NetWorker Server from Another Windows 2000 Computer .........69.
Physical Disk....................................................................................................................70.
How to Test Disk Performance for Windows NT .......................................................70.
How to Test Disk Performance for Windows 2000 ....................................................71.
Disk Performance Evaluation Methods .....................................................................72.
Disk Tuning Methods .................................................................................................72.
Memory ............................................................................................................................73.
How to Test Memory Performance for Windows NT .................................................73.
How to Test Memory Performance on Windows 2000 ..............................................74.
Memory Performance Evaluation Methods ...............................................................75.
Tuning Memory Performance in Windows.................................................................76.
How to Adjust the Virtual Memory for Windows NT ............................................76.
How to Adjust the Virtual Memory for Windows 2000 .........................................76.
How to Adjust the Physical Memory Allocation for Windows NT ........................77.
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Legato NetWorker
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Contents
How to Adjust the Physical Memory Allocation for Windows 2000..................... 77.
Memory-Related Server Tuning Methods ................................................................. 78.
CPU ................................................................................................................................. 79.
Testing CPU Performance ........................................................................................ 79.
How to Test Total CPU Utilization on Windows NT ............................................ 79.
How to Test Total CPU Utilization on Windows 2000......................................... 79.
How to Test CPU Performance by Process for Windows NT ............................. 80.
How to Test CPU Performance by Process for Windows 2000.......................... 81.
Server Input/Output ......................................................................................................... 82.
How to Test Input/Output Performance on Windows NT .......................................... 82.
How to Test Input/Output Performance on Windows 2000 ....................................... 83.
Tuning Input/Output Performance............................................................................. 83.
How to Add a Subkey Entry to the Windows Registry ........................................ 85.
Devices............................................................................................................................ 87.
How to Test Device Performance ............................................................................. 87.
Tuning Device Performance...................................................................................... 87.
How to Tune Device Performance on Windows NT ........................................... 88.
How to Tune Device Performance on Windows 2000 ........................................ 89.
Windows Software........................................................................................................... 90.
Recoveries....................................................................................................................... 91.
How to Perform Multiple, Simultaneous Recoveries ................................................. 91.
Appendix A: Troubleshooting.................................................................... 93.
RPC Error Messages....................................................................................................... 93.
Problem..................................................................................................................... 93.
Solution ..................................................................................................................... 94.
Troubleshooting Target Sessions.................................................................................... 95.
Glossary ....................................................................................................... 97.
Index ........................................................................................................... 103.
Legato NetWorker
Performance Tuning Guide
9
Contents
10
Legato NetWorker
Performance Tuning Guide
Preface
This guide provides information on how to configure and manage the Legato
NetWorker® software to maximize backup and recovery performance. It
includes tips and instructions for testing and modifying the NetWorker server
settings to ensure the most efficient configuration for your environment.
NetWorker software must be installed on the server and clients to use the
information presented here. For installation instructions, refer to the Legato
NetWorker Installation Guide.
Audience
The information in this guide is intended for system administrators who are
responsible for installing software and maintaining the servers and clients on
a network. Operators who monitor the daily backups may also find this
manual useful. Users of this guide should already be familiar with basic
NetWorker processes and services.
Product Documentation
Legato offers an extensive archive of product documentation at its web site
www.legato.com. Most of the documents are in Adobe Acrobat Portable
Document Format (PDF), and can be viewed by downloading and installing
the Adobe Acrobat Reader. The Reader is available in the /viewers/acroread
directory on the Legato Documentation Suite CD-ROM, or directly from
Adobe at www.adobe.com. To install and use the Reader on the preferred
platform, refer to the instructions in the CD-ROMs /viewers/acroread/readme.txt
file or at the Adobe web site.
Legato NetWorker
Performance Tuning Guide
11
Conventions
Conventions
This document uses the following typographic conventions and symbols to
make information easier to access and understand.
Convention
Indicates
Example
boldface
Names of line commands,
daemons, options,
programs, or scripts
The nsradmin command starts the
command line version of the administration
program.
italic in text
Pathnames, filenames,
Displayed messages are also written to
computer names, new terms /nsr/logs/daemon.log.
defined in the Glossary or
within the chapter, or
emphasized words
italic in command A variable that must be
line
provided in the command
line
fixed-width
Examples and information
displayed on the screen
nwadmin -s server-name
media waiting: recover waiting for
8mm 5GB tape volume name
fixed-width, Commands and options that nsr_shutdown -a
boldface
must be typed exactly as
shown
Menu_Name>
Command
A path or an order to follow Volume>Change Mode>Appendable
for making selections in the
GUI
Important:
Information that must be
read and followed to ensure
successful backup and
Important: Use the no_verify option with
recovery of data
extreme caution.
12
Legato NetWorker
Performance Tuning Guide
Preface
Information and Services
Legato offers a variety of methods, including electronic, telephone, and fax
support to obtain company, product, and technical information.
General Information
The Legato web site provides most of the information that customers might
need. Technical bulletins and binary patches are also accessible on the Legato
FTP site. For specific sales or training needs, e-mail or call Legato.
Legato Service or
Resource
Company &
Technical Binary Product
Training
Bulletins Patches Information Programs
www.legato.com
Yes
Yes
ftp.legato.com
(log in as anonymous)
Yes
Yes
Legato Sales
(650) 210-7000 (option 1)
[email protected]
Legato Education Services
(650) 842-9357
[email protected]
Yes
Yes
Yes
Yes
Technical Support
The Support section of the Legato web site provides contact information,
software patches, technical documentation, and information about available
support programs.
•
•
Customers with an active support agreement have access to Legato’s
integrated product knowledge base. Help with Legato software issues is
also available through Legato Technical Support.
Customers without an active support agreement can contact Support
Sales and Renewal to purchase annual Software Update Subscriptions, or
Legato Technical Support services for per-update/per-incident support.
Legato NetWorker
Performance Tuning Guide
13
Licensing and Registration
Licensing and Registration
To license and register Legato products, go to the Legato licensing web site. To
change contact information, transfer licenses, or ask questions about licensing,
contact Legato using one of the following methods.
Licensing and Registration
Contact
Legato licensing web site
http://license.legato.com
Telephone number
(650) 812 6000 (option 3, option 2)a
+31 23 554 8881b
Fax number
(650) 745-1477a
+31 23 554 8808b
E-mail
[email protected]
[email protected]
a. Contact information for Americas, Asia, and Pacific.
b. Contact information for Europe, Middle East, and Africa.
Customer Feedback
Legato welcomes comments and suggestions about software features, the
installation procedure, and documentation. Please send any suggestions and
comments to [email protected] Legato confirms receipt of all e-mail
correspondence. Although Legato cannot respond personally to every request,
all comments and suggestions are considered during product design.
Help improve Legato documentation by completing a brief survey. Visit the
Legato web site at www.legato.com, navigate to the documentation page, and
click on the link to the survey.
14
Legato NetWorker
Performance Tuning Guide
Chapter 1: NetWorker Features
The NetWorker product is a network storage management application that is
optimized for high-speed backup and recovery operations on large amounts
of complex data across an entire network of computers. The NetWorker
software is available in four editions. Brief descriptions and distinctions
between these editions are covered in this chapter, as well as an overview of
hardware and software performance, in the following sections:
•
•
"Introduction to NetWorker Editions" on page 15
"Overview of Hardware and Software Performance" on page 17
Introduction to NetWorker Editions
The four editions of the NetWorker software are as follows:
•
•
•
Workgroup Edition
The Workgroup Edition supports small networks that do not require
clustering or contain large databases and/or filesystems. The Workgroup
Edition comes with a limited number of client connections, but can easily
be upgraded to the Network Edition as needed.
Business Edition
The Business Edition is similar to the Workgroup Edition in that it is
designed for small business needs. It includes eight client connections and
support for a 2-drive/1-26 slot autochanger.
Network Edition
The Network Edition supports large, distributed networks and a full
range of add-on products.
Legato NetWorker
Performance Tuning Guide
15
Introduction to NetWorker Editions
•
1
Power Edition
The Power Edition addresses the storage management and data protection
needs of enterprises that have high-performance database servers and
fileservers, such as very large database (VLDB) applications, online
transaction processing (OLTP) applications, data warehouses, and web
servers.
Table 1 on page 16 lists the preconfigured support features for each of the
NetWorker editions.
Table 1. Preconfigured Support Features of NetWorker Editions
Workgroup
Edition
Business
Edition
Network
Edition
Power
Edition
8
8
10
10
Number of Simultaneous 12
Parallel Data Streams
12
32 + 32 per
storage node
64 + 32 per
storage node
Number of Devices
4
4
16 per server
32 per server
and/or storage and/or
node
storage node
Cluster Support
Not supported Client
Features
Number of Client
Connections
Client
Server/Client
In addition to the preconfigured features for each of the NetWorker editions,
several optional features are also supported. Table 2 on page 16 lists these
options.
Table 2. Supported Options of NetWorker Editions
Options
Workgroup
Edition
Business
Edition
Network
Edition
Power
Edition
ClientPak®
Yes
Yes
Yes
Yes
Additional Client
Connections
No
No
Yes
Yes
Library Sharing
No
No
Yes
Yes
Dynamic Drive Sharing
No
No
Yes
Yes
16
Legato NetWorker
Performance Tuning Guide
Chapter 1: NetWorker Features
Overview of Hardware and Software Performance
Performance is the speed and efficiency with which a task is completed.
Backup and recovery performance is dependent on several hardware and
software variables, but in general, backups can go no faster than the speed of
their slowest component.
This guide provides tests you can use to measure and maximize the various
components of your computer. By identifying the slowest component in the
data path between the location of the data and the storage device, you can
change software settings or replace a hardware component to improve
performance.
•
•
Factors that affect the speed of the server include the following:
– CPU
– Memory
– Input/output (I/O) bandwidth
– SCSI bandwidth
– Number of ports
Factors that affect the speed of the devices include the following:
– I/O transfer rate
– Built-in compression and initialization characteristics
Note: Device speed is combined for all storage devices used concurrently.
If clients are backed up over a network, the following factors can also affect
performance:
•
•
Client speed
– CPU
– Memory
– Disk speed
Note: Client speed is combined for all clients active at a single point in
time.
Network speed
– Network I/O bandwidth
– Network path
– Network load
Legato NetWorker
Performance Tuning Guide
17
1
Overview of Hardware and Software Performance
Factors impacting software performance include:
•
•
•
1
18
Filesystem management
Application-specific optimization
Backup application (for example, the NetWorker software)
Legato NetWorker
Performance Tuning Guide
Chapter 2: NetWorker Configuration
This chapter briefly describes the features and configurations available with
the NetWorker software, including details on how the NetWorker product
performs backups and recoveries, in the following sections:
•
•
"NetWorker Software Services and Programs" on page 19
"NetWorker Configurations" on page 25
NetWorker Software Services and Programs
This section provides an overview of how the NetWorker products perform
backup and recovery operations.
All NetWorker servers consist of services and programs that do the following:
•
•
•
•
Coordinate the tasks associated with a backup and recovery.
Record information about what was backed up.
Track the media that contains the backed-up data.
Manage storage management client configurations, client file indexes,
and the media database.
The NetWorker client software includes a client service and user interface
programs. The services and programs in NetWorker products communicate by
using the RPC protocol.
Services and Programs on the NetWorker Server
This section describes the NetWorker master service, as well as other services
and programs that reside on the NetWorker server. These services and
programs contact the client for a backup and maintain the client file indexes
and media database on the server.
Legato NetWorker
Performance Tuning Guide
19
NetWorker Software Services and Programs
The nsrd Service
The NetWorker master service, nsrd, provides an RPC-based save and recover
program function to NetWorker clients, including:
•
•
•
•
•
•
•
2
Starts other services.
Allocates media services on server computers.
Authorizes backup and recovery services for the client.
Contacts clients for scheduled backups.
Maintains NetWorker configuration information.
Monitors backup and recovery sessions.
Maintains server statistics and message logs.
Other Services and Programs
Table 3 on page 20 lists the other services and programs that reside on the
server.
Table 3. Services and Programs on the Server
Service or
Program
Function
ansrd
This service monitors an active save or recover program session. This is an
agent process spawned by nsrd in response to a save or recover session.
nsrck
This service checks the consistency of the client file index. It is invoked by
nsrd whenever the consistency of the client file index needs to be confirmed.
nsrim
This service automatically manages the server media database. This service is
invoked by nsrmmdbd when it starts up, at the end of the savegrp program,
and by nsrd when a user removes the oldest backup cycle.
nsrindexd
This service provides a method for inserting entries into the client file index
based on information passed by the save program.
nsrmmd
This service provides device support, generates mount requests, and
multiplexes save set data during a multi-client backup. The nsrd service can
start several nsrmmd services, up to twice the number of devices specified in
the server.
nsrmmdbd
This service provides media database management services to the local nsrd
and nsrmmd services and records entries in the media database. This is the
media management database service.
savegrp
This program runs a group of NetWorker clients through the save process.
20
Legato NetWorker
Performance Tuning Guide
Chapter 2: NetWorker Configuration
Services and Programs on the NetWorker Client
The nsrd service calls upon the NetWorker client service, nsrexecd, and
several programs on the client when a scheduled or on-demand backup
request is received. A temporary server agent, the ansrd service, starts on the
NetWorker server to monitor the progress of the backup session.
Table 4 on page 21 describes the services and programs on the NetWorker
client.
2
Table 4. Services and Programs on the Client
Service or
Program
Function
nsrexecd
This service authenticates the NetWorker server remote execution request
and executes the save and savefs commands on the client.
recover
This program browses the NetWorker server client file index and restores the
specified file to primary disk storage.
save
This program sends specified files in a multiplexed data stream to the
NetWorker server for backup to media by nsrmmd and entry in the client file
indexes by nsrindexd and the media database by nsrmmdbd. A level-based
system is used to save only those files which have been modified since some
previous save (a partial save).
savefs
This program gathers all the necessary information, such as filesystem and
level, and sends it to savegrp. savegrp then requests that the save program
sends the data to the NetWorker server.
How the NetWorker Software Backs Up Data
When you configure a backup group on the NetWorker server, you schedule a
start time for the backup group. The nsrd service starts the savegrp program
on the server for the backup group at the scheduled time.
The savegrp Program
The savegrp program queries the Client resources configured on the
NetWorker server to determine the following:
•
•
Which clients configured on the server are members of the scheduled
group.
What level of backup (save) to perform.
Legato NetWorker
Performance Tuning Guide
21
How the NetWorker Software Backs Up Data
•
•
How many save sets to run concurrently, determined by the parallelism
value set on the NetWorker server.
When the most recent backup of the group occurred.
If any of this information is not available on the NetWorker server, the savegrp
program sends a request (sometimes called a probe) to the nsrexecd client
service to run savefs on each client assigned to the backup group to gather the
necessary details.
The savefs program tells savegrp which objects to back up for the client. After
savegrp receives information about the objects to back up, savegrp assembles
a work list for the server. The work list specifies the order in which clients are
contacted for backup. The order of the work list is determined by the Client
Priority attribute in the Client resource. The client with the lowest value in the
Client Priority attribute is contacted first.
2
If problems were encountered with the client file index during the previous
backup session, nsrd invokes the nsrck service to check the consistency and
state of the NetWorker server client file indexes. Then, nsrd starts the
nsrindexd client file index insertion service.
The savegrp program contacts the first client on the server work list. The
nsrexecd of the client is invoked and starts a save session of the first save set
listed on the server work list. The save program passes all save criteria to nsrd,
such as group, client, save sets, and level of the save data. With this
information, nsrd determines the pool of volumes that will store the data and
forwards the information to the appropriate media service on the NetWorker
server.
The nsrmmd Service
The media service, nsrmmd, performs the following:
•
•
•
Sends a message to the NetWorker server console, requesting a mount of
the media assigned to the volume pool indicated by nsrd.
Writes the data sent by save to storage media.
Forwards storage information to nsrmmdbd for recording in the
NetWorker server media database.
Any time there is a lull in save set activity from the client, the NetWorker
server attempts to find another save set in the group to keep the process
moving. The savegrp program attempts to concurrently back up as many save
sets as possible, up to the limit set by the Parallelism attribute in the
NetWorker server configuration. This way, backup devices are utilized to their
maximum potential.
22
Legato NetWorker
Performance Tuning Guide
Chapter 2: NetWorker Configuration
The savegrp program repeats the process for each item on the server work list
until all clients in the group are backed up. Before the savegrp program
finishes, if the NetWorker server is part of the group being backed up or the
server is not part of any enabled group, the NetWorker server bootstrap file is
backed up.
If you have set up the bootstrap notification and installed and configured
TCP/IP print services, a bootstrap printout is sent to the default printer
configured for the NetWorker server after the bootstrap backup finishes.
Note: Keep the bootstrap printout in a safe place in case you need to restore
the NetWorker server.
The final results of the savegrp execution are as follows:
•
•
On Windows NT and Windows 2000 systems, results are returned to the
server and appended to the \nsr\logs\savegrp.log file.
On UNIX and Linux systems, results are appended to the
/nsr/logs/savegrp.log file.
Figure 1 on page 24 shows how all of the NetWorker client and server services
and programs interact during a scheduled save.
Legato NetWorker
Performance Tuning Guide
23
2
How the NetWorker Server Recovers Data
Figure 1. NetWorker Services and Programs During a Scheduled Backup
NetWorker Client
Client Save Sets
NetWorker Server
Client
File Index
Storage Medium
Media
Database
2
save
nsrindexd
nsrmmd
nsrexecd
savefs
nsrmmdbd
nsrd
savegrp
Legend
xxxx
Daemon
Inter-process
Communication
Data
Tracking
Information
How the NetWorker Server Recovers Data
When the NetWorker server receives a recover request from a client, the nsrd
master service of the server contacts the nsrmmd media service on the server.
The nsrmmd service contacts the nsrmmdbd media database service of the
server to determine which media contain the save set requested by the recover
program. After nsrmmd finds the save set on the media, nsrmmd issues a
mount request, the media is positioned to the beginning of the save set, and the
save set stored on the mounted media is passed to nsrmmd. The media service
forwards the save set to the recover program of the client, which restores the
data to the client’s filesystem.
24
Legato NetWorker
Performance Tuning Guide
Chapter 2: NetWorker Configuration
Figure 2 on page 25 shows how the NetWorker server and client services and
programs interact while recovering data to a NetWorker client.
Figure 2. Processes and Programs During a Recover Session
NetWorker Client
Client Save Sets
NetWorker Server
Remote
Storage Medium
Media
Database
Client
File Index
2
recover
nsrindexd
nsrmmdbd
nsrmmd
nsrd
Legend
xxxx
Service
Inter-process
Communication
Data
Tracking
Information
NetWorker Configurations
This section describes various NetWorker configurations. Immediate save and
recovery is a special feature available in all NetWorker editions of the
NetWorker software (release 6.0 and later). The text and figures provided here
illustrate various setups, including:
•
•
•
•
•
"Immediate Save and Recovery" on page 26
"Local Backup and Recovery of a Client" on page 26
"Backup and Recovery of Remote Client" on page 27
"Backup and Recovery to a Storage Node" on page 28
"Local Backup to a Silo" on page 28
Legato NetWorker
Performance Tuning Guide
25
Immediate Save and Recovery
Immediate Save and Recovery
During a backup session on a NetWorker server or storage node, the
NetWorker software distinguishes whether the data resides on the same or
remote computer.
•
2
•
When the data resides on the same computer, immediate saves and
immediate recoveriess are invoked automatically. Instead of transferring
data across the network, local data is transferred within memory on the
NetWorker server or storage node.
When the data resides on a remote client, the data is transferred over the
network by using TCP/IP.
Performance for remote backup is improved through RPC enhancements. The
examples in the following sections illustrate when immediate save can, and
cannot, be invoked.
Local Backup and Recovery of a Client
When one computer includes either both the client and server software, or the
storage node software, and they have storage devices attached, the data is
backed up through immediate save. Figure 3 on page 26 shows an example of
a local backup of a NetWorker server. The NetWorker software can back up
data of any type supported by a NetWorker client, including a range of
databases.
Figure 3. Local Backup and Recovery
Storage Device
NetWorker Server
SCSI Connection
NetWorker Client
NetWorker Module Client
Processes and data that travel through a protocol stack in a standard setup are
passed in memory on the same computer. With immediate save, the network
transmission blockage is eliminated. The same is true for recovery operations.
26
Legato NetWorker
Performance Tuning Guide
Chapter 2: NetWorker Configuration
If a database is offline, that database can take advantage of immediate save for
local backup with a NetWorker client. Some NetWorker Module clients can
also take advantage of immediate save for online database backups. To
determine whether immediate save for online backup is supported, refer to the
documentation that accompanied the NetWorker Module software.
Backup and Recovery of Remote Client
Figure 4 on page 27 shows an example of the NetWorker server installed on a
computer other than the one where the data resides.
Figure 4. Remote Backup and Recovery
Fileserver
NetWorker Server
TCP/IP
Connection
Fileserver NetWorker
Client
Storage Device
SCSI
Connection
NetWorker Client
Because the NetWorker client and the fileserver data reside on a remote
computer, the data is transferred across the network during backup.
For a recovery, the process is reversed. When the NetWorker client on the
fileserver computer makes a recovery request, the data is again transferred
across the network.
Backup and recovery performance over the network is enhanced because of
Remote Procedure Call (RPC) protocol enhancements. They prevent slower
clients from slowing down the backup of faster clients. Data that resides on the
NetWorker server is automatically backed up through immediate save (or
automatically recovered by using immediate recover).
If the data is backed up to a high-speed device, performance is improved. The
device can transfer data in less time and write it in larger blocks.
Legato NetWorker
Performance Tuning Guide
27
2
Backup and Recovery to a Storage Node
Backup and Recovery to a Storage Node
Figure 5 on page 28 shows an example of a NetWorker server that uses a
storage node for backup and recovery operations. This feature is only available
with the Power Edition or Network Edition of the NetWorker software.
Data hosted on each NetWorker storage node is backed up and recovered by
using immediate save and immediate recover technology. The metadata
associated with backups is transferred over the network to the controlling
NetWorker server, and the data is transferred directly to devices attached to
the storage node.
2
NetWorker storage nodes enable you to design scalable configurations.
•
•
Multiple devices can be attached to multiple storage nodes.
Data transfer operations can run concurrently.
Figure 5. Backup and Recovery with a NetWorker Storage Node
NetWorker Server
Storage Node
TCP/IP Connection
NetWorker Client
Storage Device
SCSI Connection
Storage Node
NetWorker Client
Local Backup to a Silo
When you add a silo to the local backup scenario, performance may improve
because of the speed and number of devices in the silo. The silo requires
another computer to be the silo server, which controls the robotics in the silo.
The silo server cannot be the same computer as the NetWorker server.
In Figure 6 on page 29, a silo and its silo server are used in the NetWorker local
backup and recovery configuration.
28
Legato NetWorker
Performance Tuning Guide
Chapter 2: NetWorker Configuration
Figure 6. Local Backup to a Silo
NetWorker Server
Computer
TCP/IP Connection
Database Server
Silo Server
(Robotics Driver)
NetWorker Client
NetWorker Module Client
(XBSA Library)
SCSI
2
SCSI
Silo Client
(Silo Tape Library Interface
library and device drivers)
Silo
During Backup
During backup, save is invoked to transfer data from the NetWorker client
processes to the NetWorker server processes in the memory of the NetWorker
server computer. If the data is written to a device in a silo, the nsrmmd service
initiates a Silo Tape Library Interface (STLI) call to the silo server, for example,
to mount a tape.
The STLI call is transferred across the network connection to the silo server,
then over a SCSI connection to the device in the silo. The data is transferred
over a SCSI connection from the NetWorker server to the device.
During Recovery
During a recovery, the process is similar to a backup. Media handling
information is transferred across the network connection from the NetWorker
server to the silo. The silo mounts the tapes, and then the data is transferred
over the SCSI connection to the NetWorker server computer, where the data is
transferred in memory to the NetWorker client process.
For more information about silos and how they interact with the NetWorker
software, refer to the Legato NetWorker Administrator’s Guide.
Legato NetWorker
Performance Tuning Guide
29
Local Backup to a Silo
2
30
Legato NetWorker
Performance Tuning Guide
Chapter 3: Testing and Tuning Basics
Improving the performance of data storage management is more an art than a
science. If the data storage management process is operating poorly or not at
all, the cause can be traced to a single problem. If the storage management
environment seems generally OK, but is not reaching the performance levels
you want, you might need to investigate and tune multiple elements in the
environment.
This chapter identifies the different hardware and software components that
make up the data storage management environment, discusses their impact on
storage management tasks, and provides general guidelines for locating
problems and solutions in the following sections:
•
•
•
•
•
•
"Overview of Performance Testing and Tuning" on page 32
"Server Hardware" on page 33
"NetWorker Settings" on page 41
"Backup Devices" on page 44
"File Type Device and Staging" on page 49
"Network Hardware" on page 51
The last two chapters of this guide address specific performance tests and
fixes, particularly those that pertain to the specific operating system on which
you are using the NetWorker software.
Legato NetWorker
Performance Tuning Guide
31
Overview of Performance Testing and Tuning
Overview of Performance Testing and Tuning
The benchmark tests used in the computer industry are done in controlled
environments, to simplify analysis and show products at their greatest
advantage. When you test the performance of the NetWorker server in your
environment, you must decide the degree to which the test is controlled.
•
•
3
To run a fully-controlled test, turn off all extraneous processes to isolate the
performance of the NetWorker server. The results of this type of test show
you the optimal performance of the NetWorker server with the current
hardware and software configuration.
To run a less-controlled test, do not shut down other applications and
network traffic. The results of this type of test show you how the
NetWorker server performs while the computer is running other
programs and processes.
If you run both a controlled test and one with a normal or simulated load, the
difference between the results can help you determine the following:
•
•
How to schedule the backups.
Whether to run other programs on the NetWorker server.
The tests in this and the following chapters follow a basic process:
1. Measure the current performance of the NetWorker server.
2. View the results to find a blockage or limiting factor.
3. Adjust the hardware and software to correct the blockage.
4. Measure the performance of the NetWorker server.
Although there will always be some blockage in a system, you can use this
process to eliminate the greatest obstacles to fast backup performance.
Note: You must have sufficient computer and network hardware installed to
support a storage application. Failure to meet minimum system requirements,
particularly for memory, free space, and CPU speed, can have an obvious and
immediate negative impact on the storage management processes.
32
Legato NetWorker
Performance Tuning Guide
Chapter 3: Testing and Tuning Basics
Server Hardware
The following sections address different hardware components of the
NetWorker server, as well as tests on the performance of these components.
Physical Disks
The physical disks in a computer system are in constant motion, reading and
writing data for storage and recovery and maintaining the client file indexes
and media database. Problems with these disks can negatively affect every
level of performance within a storage management environment.
The type of data you back up and how it is laid out on the disk can cause
backup performance to vary. If you have large files that are fragmented, or if
you have many small files, the efficiency of the disk suffers because the disk
head has to move frequently from one fragment or file to another. The backup
process is most efficient for large files with minimal fragmentation.
If the data is compressed on the disk, the operating system or application has
to decompress the data before transferring it for backup. The CPU spends
cycles to decompress the files, and the disk can rarely go at its maximum
speed.
Disk Read Speed Testing Methods
Follow these guidelines to determine the read speed of disks:
•
•
•
•
Test the read speed of each individual disk, while NetWorker software is
not running.
Test the read speed of all disks, while the NetWorker software is not
running.
Test the read speed of each individual disk, while NetWorker software is
running.
Test the read speed of all disks, while NetWorker software is running.
You can use the NetWorker uasm program, which saves and recovers
filesystem data, to test how fast the system can read from disk.
The syntax is as follows:
uasm -s [-benouv] [-ix] [-t time] [-f proto] [-p ppath] path
uasm -r [-nuv] [-i {nNyYrR}] [-m src = dst] [-z suffix] path
uasm -c [-nv] path
Legato NetWorker
Performance Tuning Guide
33
3
Physical Disks
For example, enter the following command at the system prompt:
uasm -s filename > /dev/null
where filename is a fairly large file that has not been accessed recently. If the file
was recently accessed, it may still be in memory and uasm would not actually
read the file from disk.
The uasm program reads from the disk at the maximum speed. In this
example, the data is written to a null location so the disk read is not slowed
down to allow time for writing.
The uasm program has three modes: save, recover, and compare. For a
description of how the uasm program performs in the three modes, see Table
5 on page 34.
Table 5. uasm Program Modes
3
In this mode:
The uasm program performs the following:
save
Scans directory trees and generates a save stream
on its standard output (stdout) representing the
files and organization of the directory tree.
Symbolic links are never followed by application
specific modules (ASMs), except rawasm, which
enables NetWorker to process data in raw disk
partitions.
recover
Reads a save stream from its standard input
(stdin) and creates the corresponding directories
and files.
compare
Reads a save stream from its stdin and compares
the save stream with the files already on the
filesystem.
In save mode, uasm can be controlled by directive files. Directive files control
the following:
•
•
•
•
34
How descendent directories are searched.
Which files are ignored.
How the save stream is generated.
How to process subsequent directive files.
Legato NetWorker
Performance Tuning Guide
Chapter 3: Testing and Tuning Basics
All ASMs accept the options described in Table 6 on page 35. ASMs can also
have additional options. The additional options for a particular ASM are in
capital letters.
Note: Either -s (save), -r (recover) or -c (compare) mode must be specified
when using the uasm program and must precede any other options. When
saving, at least one path value must be specified. The path value can be either
a directory or a filename.
Options Valid for All Modes of uasm
Table 6 on page 35 lists the options that are valid with all modes of uasm.
Table 6. uasm Options
Option
Usage
-n
Use the -n option to perform a dry run.
3
When saving, scan the filesystem but do not attempt to open files
and produce the save stream.
When recovering or comparing, consume the input save stream
and do basic checks, but do not create directories or files when
recovering or do the work of comparing the file data.
-v
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Use the -v option to turn on verbose mode. The current ASM, its
specified options, and the file it is processing are displayed.
When an ASM is operating in filtering mode (that is, processing
the save stream of another ASM) and modifies the stream, its
name, specified options, and the current file appear within
square brackets.
35
Physical Disks
Options for Save Mode
Table 7 on page 36 lists the options that can be used in save mode.
Table 7. Save Mode Options (Part 1 of 2)
Use this
option
To
Produce a byte count. This is similar to the -n option, but byte -b
count estimates the amount of data to be produced, instead of
actually reading file data. This option is faster but less
accurate than the -n option. Byte count mode produces three
numbers: the number of records (files and directories), the
number of bytes of header information, and the approximate
number of bytes of file data. Byte count mode does not
produce a save stream, so its output cannot be used as input to
another ASM in recover mode.
3
Produce an "old style" save stream that can be handled by
older NetWorker servers.
-o
Do not specify the -e option, because uasm does not generate
the final "end of save stream" boolean. Use this option only
when both of the following apply:
• ASM invokes an external ASM.
• An optimization does not consume the generated save
stream itself.
-e
Ignore all save directives from .nsr directive files found in the -i
directory tree.
Specify the location of a .nsr directive file to interpret before
-f
processing any files. Within the directive file specified by
proto, path directives must resolve to files within the directory
tree being processed, otherwise their subsequent directives
will be ignored.
Specify the path with ppath. When you specify -p ppath, this
-p
string is added to the beginning of each filename as it is
output. This option is used internally when one ASM execs
another external ASM. The path you enter for ppath must be a
properly formatted path that is either the current working
directory, or a trailing component of it.
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Table 7. Save Mode Options (Part 2 of 2)
Use this
option
To
Specify a date with -t date to set the date after which files must -t
have been modified before they are saved.
Specify -x to cross filesystem boundaries. Normally, filesystem -x
boundaries are not crossed when walking the filesystem.
Symbolic links are never followed, except in the case of
rawasm.
Options for Recover Mode
3
Table 8 on page 37 lists the options that can be used in recover mode.
Table 8. Recover Mode Options
To:
Use this
option
Define the initial default overwrite response option. Only one -i {nNyYrR}
overwrite response option is allowed. When the name of the
file being recovered conflicts with an existing file, the user is
prompted for overwrite permission. The default response
option, selected by pressing Return, is displayed within
square brackets.
For additional information about the -i option, see "The -i
Option" on page 38.
Map the filenames to be created. Any files that start exactly
with src are mapped to have the path of dst replacing the
leading src component of the pathname. This option is useful
if you want to perform relocation of the recovered files that
were saved using absolute pathnames into an alternate
directory (for example, -m c:\win32app=.).
-m src=dst
Specify the suffix to append when renaming conflicting files.
The default suffix is R.
-z suffix
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Physical Disks
The -i Option
The -i option defines the initial default overwrite response option. Table 9
on page 38 lists the overwrite response options and their meanings:
Table 9. Overwrite Response Options
Option Meaning
3
n
Do not recover the current file. This is the initial default overwrite
response option. Each time a response option other than the
default is specified, the new response option becomes the default.
N
Do not recover any files with conflicting names.
y
Overwrite the existing file with the recovered file.
Y
Overwrite all files with conflicting names.
r
Rename the conflicting file. A dot, “.”, and a suffix (by default
“R”) are appended to the recovered filename. If a conflict still
exists, the NetWorker software prompts you again.
R
Automatically renames conflicting files by appending a dot, “.”,
and a suffix. If a conflicting filename already ends in a “.” suffix,
the NetWorker software prompts you to avoid potential
auto-rename looping conditions.
When you specify either N, R, or Y, you are prompted only when the
NetWorker server cannot auto-rename a file that already ends with the
rename suffix, and each subsequent conflict is resolved as if the
corresponding lower-case letter had been selected.
Disk Performance Tuning Methods
If you find a blockage in the disk system, you can make the following changes
to improve performance:
•
•
•
•
•
•
38
Defragment files to reduce the number of disk seeks.
Use larger files or fewer files to reduce the number of disk seeks.
Change to a faster SCSI adapter, with synchronous I/O support and bus
mastering.
Use stripe sets on multiple disks to accommodate large files and
databases, so the physical disks can work in parallel to read data.
Spread disk-intensive programs onto different servers.
Purchase disks with higher transfer rates.
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Memory and CPU Usage
Each backup session requires CPU and memory resources on the NetWorker
server. If other applications are running concurrently with the backup, they
impose an additional load on the system. Heavy swapping or paging activities
indicate that the server is CPU- or memory-bound.
Memory Usage
A NetWorker server or storage node computer can never have too much
memory. Data transfer within memory is much faster than over a network.
Memory holds frequently used data so the disk does not have to be read as
often. Open applications, processes in run mode, and disk cache all use
memory. If the operating system is capable, disk storage space can be used as
simulated memory, often known as virtual memory.
For best results, install the maximum amount of memory that your computers
will sustain, especially for the NetWorker server and storage nodes.
CPU Usage
To increase CPU performance and bandwidth:
•
•
•
Upgrade to a faster CPU.
Add additional CPUs if the NetWorker server supports multiple
processors.
Shut down other processes during backup time.
This may reduce the processor load and improve backup performance.
Set scheduled backups for low-traffic periods to avoid performance
degradation or excessive network traffic. The default NetWorker backup start
time is 3:33 a.m.
The operating system of a computer might contain various utilities for testing
and tuning CPU speed. Additionally, you can check the CPU utilization of
each NetWorker function. The processes involved in a NetWorker backup are
the following:
•
These NetWorker services
– nsrexecd
– nsrd
– nsrmmd
– nsrmmdbd
– nsrindexd
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Server Input/Output
•
•
The save program for NetWorker backups
Application-specific services, such as for a database server
Note: To measure and record CPU speed for the NetWorker server on the
Windows platform, you can use the Windows NT or Windows 2000
Performance Monitor. See "Testing CPU Performance" on page 79.
Server Input/Output
The following performance variables relate to the input/output (I/O)
throughput on the NetWorker server.
Input/Output Backplane
On a well-configured NetWorker server, the maximum data transfer rate of the
server's I/O backplane is the limiting factor for backup throughput. The
theoretical backup throughput limitation is the following formula:
3
Backup throughput = Maximum I/O throughput/2
At a minimum, the NetWorker server requires two I/O transactions per data
block:
•
•
A read from the disk to memory
A write from memory to media
SCSI I/O Bandwidth
SCSI bus performance depends on the technology deployed. Some
specifications for different types of SCSI technology include the following:
•
•
•
•
SCSI-2 single-ended, 10 MB/sec
FWD (fast-wide-differential), 20 MB/sec
UltraSCSI, 40 MB/sec
Fibre
Note the following:
•
•
40
The rated speeds of SCSI buses are defined as "best case".
The selection of UltraSCSI-compatible devices is limited.
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NetWorker Settings
The NetWorker software has several attributes that control the speed and
volume of data being backed up. You can adjust these attribute settings to
modify backup levels to attain the best performance on the NetWorker server.
The following sections address the various NetWorker settings in principle.
Because these attributes appear in different locations in the Windows and
UNIX versions, refer to the Legato NetWorker Administrator’s Guide for specific
instructions on how to access these settings based on the server platform.
Server Parallelism
The server Parallelism attribute controls how many savestreams the server
accepts at the same time. The more savestreams the server can accept, the
faster the devices and client disks run, up to the limit of their performance or
the limits of the connections between them.
Client Parallelism
The client Parallelism attribute controls how many savestreams a client can
send at the same time. To avoid disk contention, do not set a value for client
parallelism that is higher than the number of physical disks on the client.
Multiplexing
The Target Sessions attribute sets the target number of save streams to write to
a device at the same time. Because this value is not a limit, a device might
receive more sessions than the attribute specifies. The larger the number of
sessions you specify for target sessions, the more save sets that can be
multiplexed (or interleaved) onto the same volume.
Performance tests and evaluation can help determine whether multiplexing is
appropriate for the system. Follow these guidelines when evaluating the use
of multiplexing:
•
•
Find the backup rate of each disk on the client. Use the uasm test
described in "Disk Read Speed Testing Methods" on page 33.
Find the maximum rate of each device. Use the bigasm test described in
"Test Device Performance with bigasm" on page 48.
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Modifying Settings for Performance Tuning
If the sum of the backup rates from all disks involved in a backup is greater
than the maximum rate of the device, do not increase server parallelism. If
more save groups are multiplexed in this case, backup performance will not
improve, and recovery performance could slow down.
Modifying Settings for Performance Tuning
This section describes measures you can take to improve NetWorker server
performance related to the following:
•
•
•
•
Parallelism and Target Sessions attribute settings
Workload balance
Multiplexing
Backups across a network
3
Parallelism and Target Sessions Attribute Settings
Follow these guidelines to adjust the Parallelism and Target Sessions attributes
for the best server performance:
•
•
•
•
42
Set the server Parallelism and Target Sessions attributes so that the total
of the performance of the disk drives equals the total performance of the
tape drives. If you set the Parallelism attribute to a higher value, there is
no benefit.
To select the right values for the Parallelism and Target Sessions attributes,
use the following equation:
Parallelism = Number of Devices * Target Sessions
For example, if you have three tape drives available for backup, and you
want each tape drive to accept two savestreams, set the value of server
parallelism to 6 and the value of target sessions to 2.
When a NetWorker server is saving a large number of save sets, such as
500 or more, memory consumption and file descriptor consumption can
reach values that are close to operating system limitations. In this event,
the parallelism may need to be lowered.
Decrease the server Parallelism and Target Sessions attributes to unload
an overworked NetWorker server. With the correct settings, the normal
operation of the computer should not be interrupted by backups or other
NetWorker server activities.
Add more memory to handle a higher parallelism setting.
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Chapter 3: Testing and Tuning Basics
Workload Balance
The following are recommended to avoid overloading the server:
•
•
•
Increase CPU power by upgrading the CPU or adding additional CPUs to
the server (if possible).
Reduce server load by spreading backups across multiple servers or
storage nodes.
Balance the number of disks and devices, so that the backups finish at
about the same time. For instructions on how to change these settings,
refer to the Legato NetWorker Administrator’s Guide.
Here are some methods of balancing the work load on disks and devices:
– In general, start backups for the slowest or the biggest disk volumes
first, because other disks can join in later to match the maximum
bandwidth of the device.
– Use pools of media to force the bigger and faster disk volumes to
back up to faster devices.
– If you have a very large and fast disk volume and many tape drives,
you can manually divide the volume into several save sets, such that
each of them can go to each tape drive in parallel.
– Balance data load for simultaneous sessions more evenly across
available devices by adjusting the Target Sessions attribute. This
parameter specifies the minimum number of save sessions that must
be established before the NetWorker server attempts to assign save
sessions to another device.
Multiplexing
Refer to the following guidelines for improving server performance through
multiplexing:
•
•
To fully use the bandwidth of a high-speed device when you have many
slow clients or disks, multiplex the save sets on the media. You maximize
the performance of the devices, since they do not have to start and stop to
wait for data.
To improve recovery performance, multiplex save sets that you will
recover together onto the same tape. For example, multiplex the disks of
the same computer onto the same media, because it is likely that the data
from all the disks would be recovered at the same time.
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Backup Devices
Backups Across a NetWork
In cases where you back up data across a network, the following suggestions
can also improve performance:
•
•
•
•
3
Increase the client Parallelism attribute, especially for clients with a
logical volume manager and several physical disks. The bandwidth of the
network could limit the number of savestreams you can transmit at one
time.
To reduce server load, split backups across multiple servers.
Turn on data compression in the NetWorker client to improve effective
data throughput and reduce network traffic.
Configure clients with high transfer rate requirements to have a
preference for a particular backup server on the same subnet; avoid
router hops between the NetWorker server and its clients.
Backup Devices
NetWorker software and other storage management products use backup
devices to do the following:
•
•
Write backed-up data to the storage media volume.
Read saved data from the storage media during recoveries.
Devices pass data to and from the NetWorker server itself, or from a
NetWorker storage node through a SCSI connection. Backup devices can
include optical disks, and in most cases, tape drives. When a backup device
has multiple drives, such as for autochangers, each drive is considered a
separate device.
Device Write Performance Tuning Methods
If the disk read speed is noticeably faster than the ability of the device to write,
that might indicate a problem with the write performance of the device. To
perform a thorough evaluation of device performance, follow these
guidelines:
1. Measure the write speed of each individual device, while the NetWorker
software is not in run mode.
2. Measure the write speed of all devices, while the NetWorker software is
not in run mode.
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3. Measure the write speed of each individual device, while the NetWorker
software is in run mode.
4. Measure the write speed of all devices, while the NetWorker software is in
run mode.
First evaluate the device performance without the NetWorker software
running, and then evaluate the devices again with the NetWorker software
running.
To ensure consistency in the measurements, make sure you use the same tape
drives for all tests.
Testing Tape Device Performance without Running NetWorker
The mt program can be used to determine tape device performance when the
NetWorker software is not running. Use it to evaluate the tape device without
a need to consider the overhead incurred when using the NetWorker software.
The mt program allows you to operate a magnetic tape device, which includes
rewinding, fast-forwarding, and ejecting tapes.
Note: The mt program cannot be used to measure the writing data rate, but can
indicate performance rates related to having tapes start off loaded and
rewound prior to measuring write speeds to tape.
How to Determine Tape Device Performance
To determine tape device performance when NetWorker software is not
running, enter the following at the command line:
mt -f devicename command count
By default, the mt program performs the requested operation once. To perform
the operation more than once, specify a value in place of count.
The mt program returns the following exit status:
•
•
•
0 if the operations were successful.
1 if the command was unrecognized or mt was unable to open the
specified tape drive.
2 if an operation failed.
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3
Device Write Performance Tuning Methods
Table 10 on page 46 lists the available commands to use with the mt command.
Important: Older UNIX systems may have different options for the mt
command. Before using the mt command, check the mt man page on your
system for the available options.
Table 10. Commands to Use with the mt Command
Enter this
Command:
To:
3
Write count end of file (EOF) marks at the current position
on the tape.
eof, weof
Forward space over count EOF marks. The tape is
positioned on the first block of the file.
fsf
Forward space count records.
fsr
Backspace over count EOF marks. The tape is positioned on bsf
the beginning-of-tape side of the EOF mark.
Backspace count records.
bsr
Backspace count files. The tape is positioned on the first
nbsf
block of the file. This is equivalent to count + 1 bsf followed
by one fsf.
Absolute space to count file number. This is equivalent to a
rewind followed by fsf count.
asf
Table 11 on page 46 lists the available commands where count is ignored.
Table 11. Available mt Commands with Count Ignored (Part 1 of 2)
Enter this
Command:
To:
46
Space to the end of recorded media on the tape.This is
useful for appending files onto previously written tapes.
eom
Rewind the tape.
rewind
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Table 11. Available mt Commands with Count Ignored (Part 2 of 2)
Enter this
Command:
To:
Rewind the tape and, if appropriate, take the drive unit
offline by unloading the tape.
offline, rewoffl
Print status information about the tape unit.
status
Rewind the cartridge tape completely, then wind it
forward to the end of the reel and back to the
beginning-of-tape to smooth out tape tension.
retension
Erase the entire tape.
erase
Format the tape at a low level.
format
3
Limitations
Not all tape devices support all options. Some options are
hardware-dependent. For example, by entering the following command on a
Windows computer:
D:\>mt -f \\.\Tape0 status
the following output is displayed:
\\.\Tape0:
Media Capacity
= 2.12GByte
Media Remaining = 3.06GByte
Media Block size = 0
Media Partition Count = 0
Media is not write protected
default block size = 8192
maximum block size = 1040384
The maximum block size value limits the maximum number of bytes per SCSI
transfer on disk reads and volume writes.
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Device Performance Tuning Methods
How to Test Device Performance with bigasm
To measure SCSI throughput and the write speed of a device while the
NetWorker software is running, run the bigasm module. The bigasm module is
run from a directive and generates a file of the specified size, transfers it over
a SCSI connection, and writes it to a tape or optical device.
The description and options of bigasm (and all other application specific
modules) are the same as for the uasm module. For a full description of the
uasm module, see "Disk Read Speed Testing Methods" on page 33.
To set up a bigasm test:
1. Create a file, bigasm.file, that contains the following command:
bigasm -Ssize : filename
For example:
bigasm -S100M : bigfile
3
2. Save the file using the NetWorker server. For example, if the directive file
is called bigasm.file and the NetWorker server is called jupiter, enter the
following command:
save -s jupiter -f /bigasm.file /tmp/filename
The amount of time it takes for the backup to complete indicates the
efficiency of the SCSI throughput and the write speed of the device.
The bigasm module can also be used in a scheduled backup by creating a
directive for it in the nwadmin program.
Device Performance Tuning Methods
The following sections address specific device-related areas where you can
improve performance.
Input/Output Transfer Rate
Input/output (I/O) transfer rates can affect device performance. The I/O rate
is the rate at which data can be written to the device. Depending on the device
and media technology, device transfer rates can range from 500 KB per second
to 20 MB per second. Default block size and buffer size of a device affect its
transfer rate. If you believe that I/O limitations are hampering improved
performance of the NetWorker server, try upgrading the equipment to affect a
better transfer rate.
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Built-In Compression
Turn on device compression to increase effective throughput to the device.
Some devices have a built-in hardware compression feature. Depending on
how compressible the backup data is, this can improve effective data
throughput, from a ratio of 1.5:1 to 3:1.
Drive Streaming
To obtain peak performance from most devices, stream the drive at its
maximum sustained throughput. Without drive streaming, the drive must
stop to wait for its buffer to refill or to reposition the media before the drive can
resume writing. This can cause a delay in the cycle time of a drive, depending
on the device.
3
Device Load Balancing
Balance data load for simultaneous sessions more evenly across available
devices by adjusting sessions per device. This parameter specifies the
minimum number of save sessions that must be established before the
NetWorker server attempts to assign save sessions to another device.
File Type Device and Staging
The NetWorker software includes file type and advanced file type devices and
save set staging features, which you can use to improve backup performance.
Since reading and writing data to disk is generally faster than to tape or optical
media, you can use the file type or advanced file type device feature to direct
the backups to disk media instead of tape or optical media.
The advanced file type (adv_file) is designed for very large disk devices. It
differs from the file type device because the volume for the advanced file type
device is never marked full.
When an advanced file type device runs out of disk space, the current backup
is suspended. The following message is displayed:
Filesystem full - recover adv_file space
Immediately after the message is displayed, the NetWorker software begins
deleting expired save sets until more space is made available. If enough space
has been cleared, the backup continues.
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Configuration of File Type and adv_file Devices
Use save set staging in conjunction with backups to the file type or adv_file
device. Save set staging lets you move save sets you have backed up from one
medium to another according to criteria you set, such as:
•
•
Space remaining on the disk.
Age of the save set.
With staging, you can automate transferring older backups from the file type
device or adv_file device to a less expensive storage media. This frees up hard
disk space for new backups.
Configuration of File Type and adv_file Devices
A possible configuration to maximize performance of file type or an adv_file
device is as follows:
3
1. Create one directory per user, preferably with a mnemonic name matching
a client.
2. Create one file type or adv_file device per directory, setting the volume
size to 1 GB.
3. Create one client per system, setting the device that is always used to have
the matching mnemonic device name.
This configuration limits the system to 64 users or less with the NetWorker
software, since one user equals one device, and that is how many devices
Power Edition supports. However, if you use storage nodes, then you can have
64 devices per each node up to a maximum of 256 devices total for the
NetWorker server and all attached storage nodes.
If you back up the data to file type devices or adv_file devices, you get
high-speed backups to a hard drive in near real time, but the disk tends to fill
quickly with backups.
Without Save Set Staging
Without save set staging, you would have to closely monitor disk usage to
avoid running out of space for the backups, and you would either have to
move save sets to other storage media manually or create very short browse
and retention policies.
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With Save Set Staging
With save set staging, the process of moving data from disk storage to tape or
optical disk is automated, and the space that was occupied by the save set is
freed to make space for new backups. The browse and retention policies for the
save sets on tape or optical disk can be as long as you like. You can also use
save set staging to move files from other types of media, but the space is only
reclaimed on the file type device.
If you are worried about disk contention when you back up to file type or
adv_file devices, you can use many smaller drives (for example, 6 drives of 4
GB each and 4 users per drive, instead of one 23 GB drive).
You can also use a RAID array, which provides redundancy in case of a drive
failure. Windows NT and Windows 2000 include a software RAID capability
that works well, but uses many CPU cycles. A hardware RAID solution is more
efficient, but this solution is more expensive.
Network Hardware
If you back up data from remote clients, the routers, network cables, and
network interface cards affect the backup and recovery operations. This
section lists the performance variables in network hardware and suggests
some basic tuning for networks. The following items address specific network
issues:
•
•
•
Network Input/Output Bandwidth
The maximum data transfer rate across a network rarely approaches the
specification of the manufacturer because of network protocol overhead.
Network Path
Networking components such as routers, bridges, and hubs consume
some overhead bandwidth, which degrades network throughput
performance.
Network Load
Other network traffic limits the bandwidth available to the NetWorker
server and degrades backup performance. As the network load reaches a
saturation threshold, data packet collisions degrade performance even
more.
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How to Tune NetWork Hardware Performance
How to Tune NetWork Hardware Performance
Employ the following measures to improve network hardware performance:
•
•
•
•
Add additional network interface cards to client systems to expand
network bandwidth available to clients.
Upgrade to faster LAN media, such as 100 MB Ethernet or FDDI, to
improve network bandwidth. Note, however, that TCP packet overhead
can reduce the total transfer rate.
Configure clients that have high transfer rate requirements to show a
preference for a particular backup server (or storage node) on the same
subnet; avoid router hops between the NetWorker server and clients.
Minimize the number of network components in the data path between
the client and server.
3
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Chapter 4: Testing and Tuning on UNIX and
Linux
This chapter provides additional performance testing and tuning information
for the NetWorker server on a UNIX or Linux platform. Information pertaining
to a specific performance issue or tuning method is covered in both this
chapter and "Testing and Tuning Basics" on page 31. However, the information
here was written specifically for the UNIX and Linux environments, and
provides UNIX and Linux-based examples.
The following topics are discussed:
•
•
•
•
"Physical Disks" on page 54
"Devices" on page 57
"Using the System Activity Reporter" on page 60
"Recoveries" on page 63
The multitude of platform- and network-specific variables that can impact
UNIX or Linux system performance cannot be covered comprehensively in a
single chapter. The scope of this chapter is therefore limited to the detection
and analysis of processes that have an impact on how efficiently the
NetWorker server can perform backups and recoveries.
While there are no simple solutions to performance issues, this chapter
provides a general testing strategy for locating performance blockages. The
testing strategy uses benchmarks and baselines derived from common
utilities.
Note: This chapter assumes that you are familiar with the following:
•
•
UNIX or Linux system infrastructure, including networking and devices.
Writing shell scripts and using Linux or UNIX utilities, such as tar.
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Physical Disks
The scripts in this chapter use standard utilities. The examples are specific to
Solaris, but the scripts can be applied to most UNIX and Linux platforms with
minimal changes.
The testing strategy and scripts use the following scenario:
•
•
•
All backup processes are local (that is, not over a network).
All tape devices operate at the same speed.
Data is stored on a filesystem (no databases are used).
Physical Disks
The following sections provide information and suggestions on testing and
evaluating the read speed performance on the physical disks of the NetWorker
server. The UNIX and Linux operating systems provide several utilities for
determining disk read speed. The following sections detail their usage.
Apply the following testing strategy to collect baselines to measure tape drive
performance:
•
4
•
•
•
Test the read speed of each individual disk, while the NetWorker
software is not in run mode.
Test the read speed of all disks, while the NetWorker software is not in
run mode.
Test the read speed of each individual disk, while the NetWorker
software is in run mode.
Test the read speed of all disks, while the NetWorker software is in run
mode.
Benchmark Evaluation
The utility /bin/time reports the amount of time required to execute a
program, breaking down the total time into three components:
•
•
•
54
Real time — the time that the program takes to run as it would be
measured by a user sitting at the terminal using a stopwatch.
User time — the actual time that the computer spent executing code in
the user state.
System time — the time the computer spent executing UNIX or Linux
system code on behalf of the user.
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Note: When running the tar or uasm command, do not specify a file or
mountpoint that has been accessed recently. The file may still be in memory
and not read from the disk.
Example:
The result of running the /bin/time tar cvf - /space2 > /dev/null command on
a Solaris computer provides the following result for the mount point /space2:
RESULTS:
real
6:53.4
user
18.2
sys
1:48.1
How to Test the Read Speed of a Single Disk
To test the read speed of an individual disk:
4
1. Enter the df command to display a list of mounted filesystems and their
respective sizes.
2. Run the /bin/time utility to determine how long it takes to read each
filesystem. For example, on Solaris, enter:
/bin/time tar cf - mount_point > /dev/null
To achieve a consistent result, no other disk or system activity should be
running when you run this command.
How to Test the Read Speed of Several Disks
After you execute the /bin/time utility for each individual filesystem, measure
the read time for all the filesystems on each SCSI bus. If you are running the
disks in parallel, develop a baseline for the number of parallel disks. For
example, if there are 300 disks, and 10 are in parallel, measure the baseline for
the 10 disks.
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Benchmark Evaluation
To streamline this task, create a shell script using the editor of your choice.
Following is an example shell script from a Solaris computer that was created
for multiple disks (/space, /space2, and so forth):
/bin/time tar cf - /space > /dev/null &
/bin/time tar cf - /space2 > /dev/null &
/bin/time tar cf - /space3 > /dev/null &
...
How to Test the Read Speed of a Single Disk While Running the
NetWorker Software
To test the read speed of an individual disk using the NetWorker software:
1. Enter the df command to display a list of mounted filesystems and their
respective sizes.
2. Run the uasm program for each disk. For example, on Solaris, enter:
/bin/time uasm -s mount_point > /dev/null
Depending on the configuration of the computer, you might need to
specify the path for uasm in the command.
4
For more information on the uasm command, see "Disk Read Speed Testing
Methods" on page 33.
How to Test the Read Speed of Several Disks While Running the
NetWorker Software
Test the read speed for all the disks on a SCSI channel. If you are running the
disks in parallel, develop a baseline for the number of parallel disks. For
example, if there are 300 disks, and 10 are in parallel, measure the baseline for
the 10 disks.
To streamline this task, create a shell script using the editor of your choice.
Following is an example shell script for a Solaris computer that was created for
multiple disks (/space, /space2, and so forth):
/bin/time uasm -s /space > /dev/null &
/bin/time uasm -s /space2 > /dev/null &
/bin/time uasm -s /space3 > /dev/null &
...
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To calculate the read speed of the disk:
1. Enter the df -k command to obtain the file size (in kilobytes) of /space2:
%
df -k
Filesystem
/dev/dsk/c0t1d0s0
kbytes
1952573
used
797935
capacity Mounted on
46%
/space2
2. Divide the real time by the size (in kilobytes) of /space2.
For example, based on the result and size of /space2 above, the read speed
of /space2 is 1932 KB per second.
Compare the results of the benchmarks generated from the following:
•
•
First, from the individual disks without the NetWorker software running,
as compared to the results of individual disks running the NetWorker
software.
Then, from multiple disks without the NetWorker software running, as
compared to the results of multiple disks running the NetWorker
software.
4
Devices
Apply the following testing strategy to collect baselines to measure tape drive
performance:
•
•
•
•
Test the write speed of each individual tape drive, while the NetWorker
software is not in run mode.
Test the write speed of all tape drives, while the NetWorker software is
not in run mode.
Test the write speed of each individual tape drive, while the NetWorker
software is in run mode.
Test the write speed of all tape drives, while the NetWorker software is in
run mode.
To ensure consistency in the measurements, test the same tape drives both
when the NetWorker software is running and when it is not.
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Benchmark Evaluation
Benchmark Evaluation
Compare the results of the benchmarks generated from the following:
•
•
First, from individual drives writing data without the NetWorker software
running, as compared to the results of individual drives writing data
when the NetWorker software is running.
Then, from multiple drives writing data without the NetWorker software
running, as compared to the results of multiple drives writing data while
running the NetWorker software.
How to Test the Write Speed of a Single Tape Drive
You can also test just a single tape drive by using the commands in this section.
Important: Using the mt rewind command, followed by the dd command, can
cause the erasure of a tape. Exercise caution when using these commands.
4
To test the write speed of a single tape drive, enter the following commands
for each tape drive:
mt -f /dev/rmt/drive_name rewind
dd if=/dev/zero of=/dev/rmt/drive_name \
bs=block_size count=1;\
/bin/time dd if=/dev/zero of=/dev/rmt/drive_name \
bs=block_size count=1000
Although the block size can vary depending on the environment, a block size
value of 32 can be used for purposes of testing and examples.
How to Test the Write Speed of Several Tape Drives
Test the write speed of all the tape drives on the SCSI channel. To streamline
this task, create a shell script using the command demonstrated in "How to
Test the Write Speed of a Single Tape Drive" on page 58.
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The following is an example of a shell script for a Solaris computer that was
created for multiple drives (0mbn, 1mbn, 2mbn, and so forth):
Example:
mt -f /dev/rmt/0mbn rewind; dd if=/dev/zero \
of=/dev/rmt/0mbn bs=32k count=1; \
/bin/time dd if=/dev/zero of=/dev/rmt/0mbn \
bs=32k count=1000 &
mt -f /dev/rmt/1mbn rewind; dd if=/dev/zero \
of=/dev/rmt/1mbn bs=32k count=1; \
/bin/time dd if=/dev/zero of=/dev/rmt/1mbn \
bs=32k count=1000 &
mt -f /dev/rmt/2mbn rewind; dd if=/dev/zero \
of=/dev/rmt/2mbn bs=32k count=1; \
/bin/time dd if=/dev/zero of=/dev/rmt/2mbn \
bs=32k count=1000 &
...
4
How to Test the Write Speed of a Single Drive while Running the
NetWorker Software
To test the write speed of a single drive while running the NetWorker software:
1. Set target sessions to 1.
2. Label the tape.
3. Set up bigasm:
a. Enter the following command at the prompt to create an empty
directory:
mkdir /empty
b. Enter the following command at the prompt to go to the directory
empty:
cd /empty
c. Enter the following command at the prompt to create an empty file:
touch e
d. Using a text editor, create a .nsr file.
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Using the System Activity Reporter
e. Edit the .nsr file by adding the following directive:
bigasm -S100M : e
f. Save the file and edit the text editor.
4. Run the following script to determine the baseline:
save -s server_name /etc/motd; /bin/time save -s
server_name /empty/e
When NetWorker encounters the .nsr file, the directive results in a 100 MB
file being written to tape.
The NetWorker server automatically assigns each command to a tape, since
target sessions are set to 1.
How to Test the Write Speed of Several Drives While Running the
NetWorker Software
To test the write speed of several drives, repeat steps 1-4 in "Test the Write
Speed of a Single Drive while Running the NetWorker Software" on page 59
for every drive on the SCSI channel at the same time.
4
Using the System Activity Reporter
The System Activity Reporter (sar) is a standard UNIX utility for most systems
that monitors and reports on system performance, including buffer and block
device activity, kernel memory allocation, and CPU utilization. Use this utility
to evaluate and tune a UNIX system. For more information, refer to the sar
man page.
How to Monitor Buffer Activity
If the read and write buffer cache hit rates (%rcache and %wcache) are
consistently low, increase the size of the buffer cache to improve disk I/O
performance.
To monitor buffer read activity, enter the following command:
sar -b %rcache
To monitor buffer write activity, enter the following command:
sar -b %wrcache
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The values of %rcache and %wrcache depend on the combination of
applications that the system is running, the speed of its disk subsystems, and
the amount of memory available. The ideal value for both is 100%, but that
value is unlikely on an average system. If either value is consistently below
50%, increase the size of the buffer cache.
How to Monitor Block Device Activity
To monitor block device activity, enter the following command:
sar -d
Results similar to the following appear:
23:59:44
23:59:49
23:59:54
23:59:59
device
Sdsk-0
Sdsk-0
Sdsk-0
%busy
99.42
100.00
100.00
avque
4.18
4.18
3.98
r+w/s
39.39
38.73
38.07
blks/s
166.28
163.64
171.95
avwait
80.26
82.35
78.32
avserv
25.24
25.87
26.32
where:
•
•
•
•
•
•
•
device is the device on which the activity is being measured.
%busy is the percentage of time that the system was transferring data to
and from the device.
A consistently high value for %busy indicates a heavily utilized disk.
Increasing CPU power will create a bottleneck worse because the
processor produces more I/Os for a disk that is already overloaded.
avque is the average number of requests pending on the device including
any on the device itself.
r+w/s is the number of read and write transfers to and from the disk.
blks/s is the number of 512-byte blocks transferred per second.
The values for r+w/s and blks/s can be used to calculate the average size
of data transfers by using the following formula:
Average size of data transfer = blks/s / r+w/s
avwait is the average time in milliseconds that the request waits in the
driver before being sent to the device.
avserv is the average time in milliseconds that it takes a request to
complete. The length of time is calculated from the time that the request
was sent to the device to the moment that the device signals that it has
completed the request. The value of avserv varies depending on the type
of disk and any caching on the disk controller.
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4
Using the System Activity Reporter
Use the values generated by sar -d to determine which disks are overused and
which are underused. To avoid bottlenecks, balance the disk load by moving
some users from the busier disks to the less active disks.
How to Test CPU Utilization
The sar -u command identifies disks to which the NetWorker software writes
frequently, which could be I/O bottlenecks. To enhance performance, optimize
these disks.
To test I/O-related CPU activity, enter the following command:
sar -u
The following is reported:
•
•
•
4
•
%usr is the percentage of time the system is in user mode (that is, running
user or application code).
%sys is the percentage of time system programs or system calls are run
from user programs.
%wio is the percentage of time the system is waiting for I/O.
The %wio value should generally not exceed 25%. A higher percentage
may indicate that you need to speed up disk throughput or add I/O bus
capacity.
%idle is the percentage of time the system is completely idle.
If %idle is frequently equal to zero, the system is CPU bound. If the system
throughput is too low, upgrade to a faster processor or reduce
computational load on the system.
The following example shows how to test CPU utilization by taking five
samples at 60 second intervals.
Example:
To test CPU utilization, enter the following command:
sar -u 60 5
The following results appear:
18:22:46
18:23:46
18:24:46
62
%usr
13
25
%sys
9
16
%wio
6
13
%idle
73
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18:25:46
18:26:46
18:27:46
21
22
22
9
10
11
1
1
1
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66
66
Recoveries
Recovery performance can fluctuate based on a variety of issues, including
network traffic, bottlenecks, and file sizes. One method of recovering data
efficiently is to start multiple recover commands simultaneously through the
save set recovery method.
For example, you can start three different save set recover programs instead of
one recover program with three save sets. Separate recover programs provide
the maximum parallelism possible given the number of daemons and the
actual volume and save set layout.
Important: If multiple, simultaneous recover programs are being run from the
same tape, do not let the tape mount and start until all recoveries are ready. If
the tape is used before all recoveries are ready, the tape will be read through
multiple times and recovery performance will be slower, rather than faster.
How to Perform Multiple, Simultaneous Recoveries
To perform multiple recoveries:
1. Open one command window for each save set that needs to be recovered.
2. In each window, enter the recover command with the save set to be
recovered, but do not press [Return].
3. Once all three recover commands are ready, execute each command
consecutively.
4. Measure the time it takes to recover all three save sets.
5. Once the recoveries are finished, perform another recovery with all three
save sets in the same recover request.
6. Compare the time needed for the multiple recovery requests to the time
needed for the single recovery request.
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4
Recoveries
The multiple recoveries should have finished before the single recovery of
multiple save sets. If the single recovery completed faster:
•
•
The tape may have been mounted before all recoveries could start.
The computer is CPU-bound rather than I/O-bound.
To determine the cause of the bottlenecks, use the performance and activity
monitoring tools available with the operating system.
4
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This chapter addresses specific performance testing and tuning tasks you can
perform on a NetWorker server in a Windows environment. For a discussion
of general performance issues affecting all versions of the NetWorker software,
see "Chapter 3: Testing and Tuning Basics" on page 31.
The following topics are discussed in this chapter:
•
•
•
•
•
•
•
•
"Windows Performance Monitor" on page 65
"Physical Disk" on page 70
"Memory" on page 73
"CPU" on page 79
"Server Input/Output" on page 82
"Devices" on page 87
"Windows Software" on page 90
"Recoveries" on page 91
Windows Performance Monitor
Use the Windows Performance Monitor program to test system performance.
In the Performance Monitor, you can choose:
•
•
•
Which objects to watch, for example, the processor or memory.
Which counters to test, for example, available bytes of memory.
How to display the data.
The default view of the data is a real-time line chart. However, the data can
also be logged or formatted as a report, or alerts can be created that warn when
a counter reaches a certain limit.
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Windows Performance Monitor
How to Start the Windows NT Performance Monitor
To start the Windows NT Performance Monitor on the NetWorker server:
1. Select Start>Programs>Administrative Tools>Performance Monitor.
2. From the View menu, select Report.
The default viewing mode of the Performance Monitor is Chart, but the
Performance Monitor-related tasks in this chapter use the Report mode.
3. From the Edit menu, select Add To Report.
4. From the Object list, select which component of the NetWorker server you
want the Performance Monitor to track.
This Object choice determines the Counter and Instance choices available
to you.
5. From the Counter list box, select a choice. Click Explain to view
descriptions of each counter.
6. From the Instances list box, select a choice.
7. When all choices are selected, click Add.
The Performance Monitor window reflects the NetWorker server and the
component to be monitored.
8. Repeat steps 4-7 for each component on the NetWorker server you want to
test.
The Performance Monitor window lists each component separately under
the name of the NetWorker server.
5
9. Once all the NetWorker server components to be tested have been added,
click Done.
10. Start a backup, and view or capture the results.
To save the performance monitoring information in log form:
1. Place the Performance Monitor in Log mode.
2. From the Options menu, select Log.
3. Specify a filename and location and save the log file.
To test the maximum performance of the NetWorker software:
1. Shut down all extraneous processes.
2. Run just the necessary software on the NetWorker server.
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How to Start the Windows 2000 Performance Monitor
To start the Windows 2000 Performance monitor on the NetWorker server:
1. Select Start>Programs>Administrative Tools>Performance.
2. Right-click anywhere in the System Monitor details pane and select
Properties.
3. In the General tab, select Report.
Note: The default viewing mode of Performance Monitor is Graph, but the
Performance Monitor-related tasks in this chapter use the Report mode.
4. To open the Add Counters dialog box, select the Data tab and click Add.
5. To make sure the local computer is the one that is monitored, select Use
Local Computer Counters.
6. From the Performance Object list, select the NetWorker server component
to be tracked by the Performance monitor.
The Object choice selected determines which Counter and Instance choices
are available.
7. From the Counter list box, select a choice. Click Explain to view
descriptions of each counter.
8. From the Instances list box, select a choice.
9. When all choices are selected, click Add.
10. Click Close.
5
The Performance Monitor window displays the NetWorker server and
component to be monitored.
11. Repeat steps 4-10 for each component on the NetWorker server whose
performance you want to test.
Performance Object window lists each component separately under the
name of the NetWorker server.
12. Once all the NetWorker server components to be tested have been added,
click OK.
13. Start a backup, and view or capture the results.
To save the performance monitoring information in log form, select
Performance Logs and Alerts in the Performance window.
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Testing a NetWorker Server from Another Computer
To test the maximum performance of the NetWorker software:
1. Shut down all extraneous processes.
2. Run just the necessary software on the NetWorker server.
Testing a NetWorker Server from Another Computer
Because the Performance Monitor uses system resources, you might want to
run the Performance Monitor on a different Windows computer on the
network during controlled tests of the NetWorker server.
When the Performance Monitor is run on a different Windows system, it still
uses some resources on the NetWorker system, especially adding to network
traffic during remote backups. However, the performance of the processor and
SCSI throughput on the NetWorker system are not affected.
How to Test a NetWorker Server from Another Windows NT Computer
To test the performance of one or more NetWorker servers from another
Windows NT computer:
1. Select Start>Programs>Administrative Tools>Performance Monitor on
the monitoring Windows NT computer.
2. From the View menu, select Report.
3. From the Edit menu, select Add To Report.
4. Enter the name of the NetWorker server to be tested in the Computer text
box, either by entering the name directly or by clicking the “...” button that
allows you to browse to the appropriate NetWorker server.
5
5. From the Object list, select a choice. The Object choice selected determines
which Counter and Instance choices are available.
6. From the Counter list box, select a choice. Click Explain to view
descriptions of each counter.
7. From the Instances list box, select a choice.
8. When all choices are selected, click Add.
The Performance Monitor window displays the NetWorker server and
components to be monitored.
9. Repeat steps 5-8 for each component on the NetWorker server to be tested.
The Performance Monitor window lists each component separately under
the NetWorker server name.
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10. Repeat steps 4-8 if you want to monitor the performance of any other
NetWorker servers (or any other Windows NT computers in general).
11. When you have added all the NetWorker server components to be tested,
click Done.
12. Start a backup, and view or capture the results.
You can save, add to, and redirect the performance monitoring information
that results from this procedure. For more detailed information about the
Performance Monitor and Windows NT, refer to the Microsoft Windows NT
operating system documentation.
How to Test a NetWorker Server from Another Windows 2000 Computer
To test the performance of one or more NetWorker servers from another
Windows 2000 computer:
1. Select Start>Programs>Administrative Tools>Performance.
2. Right-click anywhere in the System Monitor details pane and select
Properties.
3. In the General tab, select Report.
Note: The default viewing mode of Performance Monitor is Graph, but the
Performance Monitor-related tasks in this chapter use the Report mode.
4. To open the Add Counters dialog box, select the Data tab and click Add.
5. Select Counters from Computer and type in the name of the NetWorker
server.
6. From the Object list, select an object. The Object choice selected determines
the Counter and Instance choices that are available.
7. From the Counter list box, select a choice. Click Explain to view
descriptions of each counter.
8. From the Instances list box, select a choice.
9. When all choices are selected, click Add.
10. Click Close.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
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5
Physical Disk
11. Repeat Steps 6-10 for each component on the NetWorker server to be
tested.
The Performance Monitor window lists each component separately under
the NetWorker server.
12. Repeat Steps 5-10 if you want to monitor the performance of any other
NetWorker servers (or any other Windows 2000 computer in general).
13. When you have completed adding all the NetWorker server components
to be tested, click OK.
14. Start a backup, and view or capture the results.
You can save, add to, and redirect the performance monitoring information
that results from this procedure. For more detailed information about the
Performance Monitor and Windows 2000, refer to the Microsoft Windows 2000
operating system documentation.
Physical Disk
This section describes how to use Performance Monitor to test and evaluate
physical disk performance problems related to the NetWorker server. For a
general discussion of disk-related performance problems and solutions, see
"Physical Disks" on page 33.
How to Test Disk Performance for Windows NT
5
To test the disk performance of the NetWorker server in the Windows NT
environment:
1. Select Start>Programs>Administrative Tools>Performance Monitor.
2. From the View menu, select Report.
3. From the Edit menu, select Add To Report.
4. From the Object list, select Physical Disk.
5. From the Counter list box, select the following counters:
– % Disk Time
– Current Disk Queue Length
To view details on each counter, click Explain.
If the NetWorker server has more than one physical disk, select these
counters for each disk.
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6. When all choices are selected, click Add.
The Performance Monitor window reflects the NetWorker server and the
component whose performance you want to monitor.
7. Click Done.
8. Start a backup, and view or capture the results.
Note: If the disk performance counters do not work, you must set Windows
NT to turn them on. Open an MS-DOS window and enter the following
command at the prompt:
diskperf -y
Restart the NetWorker server to activate the counters.
How to Test Disk Performance for Windows 2000
To test the disk performance of the NetWorker server in a Windows 2000
environment:
1. Select Start>Programs>Administrative Tools>Performance.
2. Right-click anywhere in the System Monitor details pane and select
Properties.
3. In the General tab, select Report.
4. To open the Add Counters dialog box, select the Data tab and click Add.
5. From the Object list, select Physical Disk.
5
6. From the Counter list box, select the following counters:
– % Disk Time
– Current Disk Queue Length
To view details on each counter, click Explain.
If the NetWorker server has more than one physical disk, select these
counters for each disk.
7. When all choices are selected, click Add.
8. Click Close.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
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Disk Performance Evaluation Methods
9. Click OK.
10. Start a backup, and view or capture the results.
Note: If the disk performance counters do not work, open a command prompt
window and enter the following command:
diskperf -y
Restart the NetWorker server to activate the counters.
Disk Performance Evaluation Methods
To determine if the NetWorker server has a disk-related blockage, check the
values gathered from the performance testing.
•
•
If the value for the Percent Disk Time counter exceeds 90 percent, tune the
disk performance as suggested in "Disk Tuning Methods" on page 72.
This counter measures the percentage of operating time the disk is
occupied with read or write requests.
If the value for the Disk Queue Length counter exceeds 2, tune the disk
performance as suggested in "Disk Tuning Methods" on page 72.
This counter measures the average number of read or write requests that
were waiting to be serviced during the sampling interval.
Disk Tuning Methods
The methods for tuning disk performance on the NetWorker server in a
Windows environment are the same for tuning computer disks in general,
including:
5
•
•
•
•
•
•
72
Defragment files to reduce the number of disk seeks.
Use larger files or fewer files to reduce the number of disk seeks.
Change to a faster SCSI adapter, with synchronous I/O support and bus
mastering.
Use stripe sets on multiple disks to accommodate large files and
databases, so the physical disks can work in parallel to read data.
Spread disk-intensive programs onto different servers.
Purchase disks with higher transfer rates.
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Memory
This section describes how to use the Performance Monitor to test and evaluate
memory-related performance problems related to the NetWorker server. For a
general discussion of memory-related performance problems and solutions,
see "Memory Usage" on page 39.
How to Test Memory Performance for Windows NT
To test the memory-related performance of the NetWorker server in a
Windows NT environment:
1. Select Start>Programs>Administrative Tools>Performance Monitor.
2. From the View menu, select Report.
3. From the Edit menu, select Add To Report.
4. From the Object list, select Memory.
5. From the Counter list box, select the following counters:
– Available Bytes
– Commit Limit
– Committed Bytes
– Pages/sec
To view details on each counter, click Explain.
6. When all choices are selected, click Add.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
7. Click Done.
8. Start a backup, and view or capture the results.
To analyze the results of these tests, see "Memory Performance Evaluation
Methods" on page 75.
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Memory
How to Test Memory Performance on Windows 2000
To test the memory-related performance of the NetWorker server in a
Windows 2000 environment:
1. Select Start>Programs>Administrative Tools>Performance.
2. Right-click anywhere in the System Monitor details pane and select
Properties.
3. In the General tab, select Report.
4. To open the Add Counters dialog box, select the Data tab and click Add.
5. From the Object list, select Memory.
6. From the Counter list box, select the following counters:
– Available Bytes
– Commit Limit
– Committed Bytes
– Pages/sec
To view details on each counter, click Explain.
7. When all choices are selected, click Add.
8. Click Close.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
9. Click OK.
5
10. Start a backup, and view or capture the results.
To analyze the results of these tests, see "Memory Performance Evaluation
Methods" on page 75.
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Memory Performance Evaluation Methods
Use the values gathered from the performance testing to determine if the
NetWorker server has a memory-related blockage. Table 12 on page 75 lists the
counters and which values indicate that tuning is required.
Table 12. Counter Values
Counter
Values
Available Bytes
This counter measures how much memory is not already occupied. The
smaller the value of Available Bytes, the slower the performance. If the
value is less than 4 MB, the memory performance requires tuning.
Pages/sec
This counter measures virtual memory activity; that is, how often the
memory writes to disk. When the computer is memory-bound, it pages
to the virtual memory on disk more often. A value of 20 or greater
indicates that tuning is required.
Committed Bytes This counter is the total memory of all applications in use at the moment.
Applications generally reserve more memory than they use during
regular operation. But an application does not write data to memory
without committing the memory first. So the value for Committed Bytes
shows the amount of memory the applications currently need.
If more memory is committed than you have physical memory to
accommodate, the computer pages memory contents to disk (virtual
memory), and the computer works more slowly, because physical
memory is faster than virtual memory.
Commit Limit
5
This counter is the size of virtual memory that can be committed without
having to extend the paging file. Every time the Windows computer
extends the paging file, it goes to disk and searches for more space to use
for virtual memory. This process has a high performance cost, and you
might run out of disk space. The Committed Bytes value should not
consistently exceed the Commit Limit value.
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Tuning Memory Performance in Windows
Tuning Memory Performance in Windows
The following section explains how to tune memory performance on the
NetWorker server.
Note: To determine a good baseline size for the virtual memory file
(pagefile.sys), log the Committed Bytes counter over a period of time, add 10 to
20 percent to the maximum value, and enter that value in the Initial Size (MB)
text box in the Virtual Memory dialog box.
How to Adjust the Virtual Memory for Windows NT
To adjust the allocated size of virtual memory on the NetWorker server in a
Windows NT environment:
1. Select Start>Settings>Control Panel.
2. Double-click the System icon, then click the Performance tab.
3. To open the Virtual Memory dialog box, click Change.
4. As needed, adjust the size and location of the disk space allocated to
virtual memory.
5. Click OK.
How to Adjust the Virtual Memory for Windows 2000
To adjust the allocated size of virtual memory on the NetWorker server in a
Windows 2000 environment:
5
1. Select Start>Settings>Control Panel.
2. Double-click the System icon to open the System Properties dialog box.
3. Select the Advanced tab and click Performance Options.
4. In the Performance Options window, click Change to open the Virtual
Memory dialog box.
5. As needed, adjust the size and location of the disk space allocated to
virtual memory.
6. Click OK.
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How to Adjust the Physical Memory Allocation for Windows NT
To adjust physical memory allocation on the NetWorker server in the
Windows NT environment:
1. Select Start>Settings>Control Panel.
2. Double-click the Network icon, then click the Services tab.
3. From the Network Services list box, select Server.
4. To open the Server dialog box, click Properties.
5. Select one of the following options:
–
–
–
–
Minimize Memory Used: Use when the server has fewer than 10
users, such as a local backup on a NetWorker server.
Balance: Use when the server has 10 to 64 users.
Maximize Throughput for File Sharing: Allocate most of the memory
to the fileserver module, for systems with more than 64 users.
Maximize Throughput for Network Application: Use for a
client-server application server, such as a NetWorker server with
remote clients.
6. Click OK.
How to Adjust the Physical Memory Allocation for Windows 2000
To adjust physical memory allocation on the NetWorker server in a Windows
2000 environment:
1. Select Start>Settings>Control Panel.
2. Double-click the Network and Dial-Up Connections icon.
3. Right-click Local Area Connection and select Properties.
4. In the Local Area Connection Properties dialog box, select File and Printer
Sharing for Microsoft Networks and click Properties.
5. Select one of the following options:
–
–
–
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Minimize Memory Used: Use when the server has fewer than 10
users, such as a local backup on a NetWorker server.
Balance: Use when the server has 10 to 64 users.
Maximize Throughput for File Sharing: Allocate most of the memory
to the fileserver module, for systems with more than 64 users.
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Memory-Related Server Tuning Methods
–
Maximize Throughput for Network Application: Use for a
client-server application server, such as a NetWorker server with
remote clients.
6. Click OK.
Memory-Related Server Tuning Methods
To speed up virtual memory, you can implement the disk recommendations in
"Disk Tuning Methods" on page 72. You can also defragment the disks where
pagefile.sys resides.
Note: It is not recommended to put pagefile.sys on either of the following:
•
•
A stripe set, because virtual memory is less efficient when it is
fragmented.
A mirrored drive, because every write is done twice, which slows
down writes to virtual memory.
You can also reduce the memory that the NetWorker server uses. Suggestions
to reduce memory requirements include the following:
•
•
•
5
78
Reduce the number of other applications that run on the NetWorker
server. Dedicate the NetWorker server to run the database server,
NetWorker client, NetWorker Module client, and NetWorker server.
Stop services that you do not use. For example, if you have only SCSI
devices, stop the ATDISK service, which is for IDE devices only.
Remove communications protocols you do not use. For example, if you
only use TCP/IP but you also have SPX installed, remove SPX.
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Chapter 5: Testing and Tuning on Windows
CPU
The following sections address testing and tuning issues for the NetWorker
server CPU(s). For a general discussion of how CPU issues affect NetWorker
software performance, see "CPU Usage" on page 39.
Testing CPU Performance
Total CPU utilization and CPU utilization for each individual process
demonstrate the CPU performance of the NetWorker server.
How to Test Total CPU Utilization on Windows NT
To test total CPU utilization of the NetWorker server during backup in a
Windows NT environment:
1. Select Start>Programs>Administrative Tools>Performance Monitor.
2. From the View menu, select Report.
3. From the Edit menu, select Add To Report.
4. From the Object list, select Processor.
5. From the Counter list box, select % Processor Time. Click Explain to view
details on this counter.
6. Select the processors to be tested from the Instance list box if the
NetWorker server has more than one processor.
5
7. When all choices are selected, click Add.
The Performance Monitor window displays the NetWorker server and the
component to be monitored. Click Done.
8. Start a backup, and view or capture the results.
How to Test Total CPU Utilization on Windows 2000
To test total CPU utilization of the NetWorker server in a Windows 2000
environment during backup:
1. Select Start>Programs>Administrative Tools>Performance.
2. Right-click anywhere in the System Monitor details pane and select
Properties.
3. In the General tab, select Report.
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Testing CPU Performance
4. Select the Data tab and click Add.
5. From the Object list, select Processor.
6. From the Counter list box, select % Processor Time. Click Explain to view
details on this counter.
7. Select the processors to be tested from the Instance list box if the
NetWorker server has more than one processor.
8. When all choices are selected, click Add.
9. Click Close.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
10. Click OK.
11. Start a backup, and view or capture the results.
How to Test CPU Performance by Process for Windows NT
You can also test CPU utilization for each process involved in the backup, to
determine which processes use most of the CPU capacity.
To test total CPU utilization of the NetWorker server in a Windows NT
environment during backup:
1. Select Start>Programs>Administrative Tools>Performance Monitor.
2. From the View menu, select Report.
5
3. From the Edit menu, select Add To Report.
4. From the Object list, select Process.
5. From the Counter list box, select the % Processor Time. Click Explain to
view details on this counter.
6. Select the individual services, programs, or other processes to be tested
from the Instance list box.
7. When all choices are selected, click Add.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
8. Click Done.
9. Start a backup, and view or capture the results.
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There is a CPU blockage if total CPU utilization remains above 90% for long
periods during the backup process.
How to Test CPU Performance by Process for Windows 2000
You can also test CPU utilization for each process involved in the backup, to
determine which processes use most of the CPU capacity.
To test total CPU utilization of the NetWorker server in a Windows 2000
environment during backup:
1. Select Start>Programs>Administrative Tools>Performance.
2. Right-click anywhere in the System Monitor details pane and select
Properties.
3. In the General tab, select Report.
4. Select the Data tab and click Add.
5. From the Object list, select Process.
6. From the Counter list box, select the % Processor Time. Click Explain to
view details on this counter.
7. From the Instance list box, select the individual services, programs, or
other processes to be tested.
8. When all choices are selected, click Add.
9. Click Close.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
10. Click OK.
11. Start a backup, and view or capture the results.
There is a CPU blockage if total CPU utilization remains above 90% for long
periods during the backup process.
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Server Input/Output
Server Input/Output
The following sections address testing and tuning issues for the NetWorker
server input/output (I/O). For a general discussion of how I/O issues affect
NetWorker software performance, see "Server Input/Output" on page 40.
To test the I/O of the NetWorker server most effectively, you must start and
configure the Performance Monitor, and then run specific NetWorker server
I/O-related tests. For more information about these tests, see " Server
Input/Output" on page 40.
How to Test Input/Output Performance on Windows NT
To start and configure the Performance Monitor to test the NetWorker server
I/O in a Windows NT environment:
1. Select Start>Programs>Administrative Tools>Performance Monitor.
2. From the View menu, select Report.
3. From the Edit menu, select Add To Report.
4. From the Object list, select System.
5. From the Counter list box, select File Write Bytes/sec. Click Explain to
view details on this counter.
6. When all choices are selected, click Add.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
5
7. Click Done.
8. Run the following tests, and view or capture the results:
–
–
–
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For the uasm program: See "Disk Read Speed Testing Methods" on
page 33.
For the mt program: See "Testing Tape Device Performance without
Running NetWorker" on page 45.
For the bigasm program: See "Test Device Performance with bigasm"
on page 48.
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Chapter 5: Testing and Tuning on Windows
How to Test Input/Output Performance on Windows 2000
To start and configure the Performance Monitor to test the NetWorker server
I/O in a Windows 2000 environment:
1. Select Start>Programs>Administrative Tools>Performance.
2. Right-click anywhere in the System Monitor details pane and select
Properties.
3. In the General tab, select Report.
4. Select the Data tab and click Add.
5. From the Object list, select System.
6. From the Counter list box, select File Write Bytes/sec. Click Explain to
view details on this counter.
7. When all choices are selected, click Add.
8. Click Close.
The Performance Monitor window displays the NetWorker server and the
component to be monitored.
9. Click OK.
10. Run the following tests, and view or capture the results:
–
–
–
For the uasm program: See "Disk Read Speed Testing Methods" on
page 33.
For the mt program: See "Testing Tape Device Performance without
Running NetWorker" on page 45.
For the bigasm program: See "Test Device Performance with bigasm"
on page 48.
Tuning Input/Output Performance
The rate at which a SCSI device can write data to media is limited by the
amount of data that transfers over the SCSI bus in a single I/O operation. To
tune SCSI performance, change the number of memory pages the SCSI host
bus adapter (HBA) can scatter and/or gather in a single direct memory access
(DMA). The number of bytes that can be transferred in a single I/O with a SCSI
device is limited by the number of memory pages that the SCSI host bus
adapter can scatter and/or gather in a single DMA.
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Tuning Input/Output Performance
The SCSI driver of each vendor specifies the maximum number of pages that
the HBA can scatter and/or gather for the DMA transfer. When you multiply
the page size by the number of scatter and/or gather entries, the product is the
effective limit to the number of bytes that can be transmitted in a single I/O
operation.
The equation is the following:
I/O operation size = Page size * (# of scatter/gather entries -1)
User memory is not necessarily page-aligned; therefore:
If MaximumSGList = 255 then the I/O transfer size is 4K * 254 = 1016K.
For the drivers of some SCSI host adapters, you can change the maximum
number of scatter and/or gather pages. Many tape drives and disk drives
perform better with a larger I/O limit. A change in the number of scatter
and/or gather pages can make a large performance difference. For example:
•
•
The Ampex DST tape drive writes only 3 MB per second with 64 KB SCSI
transfers and 20 MB per second with 992 KB SCSI transfers.
The SCSI disk “CYBERNET 10XP” reads 1.7 MB per second with a 32 KB
read buffer size and 17 MB per second with a 200 KB read buffer size.
To change the maximum scatter and/or gather pages setting in the Windows
Registry, add the following new Registry subkey to specify the maximum
number of scatter and/or gather list elements for each device on a given bus:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\
DriverName\Parameters\Device number\MaximumSGList
5
Important: Modifying the Registry is very dangerous. Do not attempt to
modify the Registry unless you have an up-to-date backup of the Registry to
which you can revert and you are convinced that the modification you are
about to make is correct. Inappropriate changes to the Registry can result in the
need to reinstall the Windows software.
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How to Add a Subkey Entry to the Windows Registry
To add the subkey entry to the Windows Registry:
1. Start the Windows Registry Editor program as follows:
a. Select Start>Run.
b. Enter the following value in the Open text box:
regedt32
c. Press [Enter].
Note: You can also open this program at the following location:
%SystemRoot%\Winnt\System32\regedt32.exe
2. Select Window>HKEY_LOCAL_MACHINE to make that window active.
3. Select Edit>Add Key and enter Parameters for Key Name to create a key
named Parameters, if one does not exist.
4. To create a key named Device, open the Parameters key by selecting
Edit>Add Key and enter Device for Key Name.
5. To create a DWORD named MaximumSGList, open the Device key by
selecting Edit>DWORD and entering MaximumSGList for DWORD
Name.
6. Open the MaximumSGList Value Name and replace the existing Value
Data in Decimal with a number at least as large as the block size you need
for the device.
To calculate the value, use the following equation:
(Block_Size / 4) + 1 = Value
Table 13 on page 85 provides block size and corresponding decimal and
hex values.
Table 13. Block Sizes
Block Size
Decimal Value
Hex Value
64k
17 decimal
11 hex
96k
25 decimal
19 hex
128k
33 decimal
21 hex
256k
65 decimal
41 hex
512k
129 decimal
81 hex
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7. Reboot the machine.
8. To locate the drives, run the inquire program:
C:\>inquire
Results similar to the following appear:
[email protected]:NEC CD-ROM DRIVE:4661.06|CD-ROM
[email protected]:ARCHIVE Python 06408-XXX8071|Tape,
\\.\Tape0
[email protected]:HP C5173-7000 3.02|Autochanger (Jukebox)
[email protected]:QUANTUM DLT7000 1732|Tape, \\.\Tape1
[email protected]:QUANTUM DLT7000 1732|Tape, \\.\Tape2
[email protected]:SEAGATE ST39204LC 0002|Disk,
\\.\PHYSICALDRIVE0
[email protected]:QUANTUM ATLAS V 9 SCA 0201|Disk,
\\.\PHYSICALDRIVE1
[email protected]:DELL 1x4 U2W SCSI BP 5.35|Processor
9. To check if the maximum blocksize has changed, run the mt program:
C:\>mt -f \\.\Tape1 status
Results similar to the following appear:
\\.\Tape1:
Media Capacity = 15.20GByte
Media Remaining = 13.60GByte
Media Blocksize = 0
Media Partition Count = 0
Media is not write protected
default blocksize = 65536
maximum blocksize = 131072
minimum blocksize = 1
MaximumPartitionCount = 0
Partition = 0
Logical block position = 44815
EOTWarningZoneSize = 0
CompressionEnabled
Features: ...
In the above example, the maximum block size is 128 KB (131072 divided
by 1024).
5
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Other suggestions for tuning I/O performance are as follows:
•
•
•
•
•
•
Move the hardware configuration around; for example, move some disks
off a SCSI bus that is overloaded.
If possible, use PCI adapters in the NetWorker server. If you must use
other adapters, EISA adapters are better than ISA adapters, because ISA
adapters have bus contention problems that degrade system
performance.
Use a dual PCI backplane system, rather than a bridged PCI backplane.
Use multiple SCSI buses with devices of the same type (for example,
UltraSCSI) on the same bus.
Use short, high-quality cables with active terminators.
Ensure that SCSI communications are occurring synchronously, not
asynchronously.
Devices
The following sections address testing and tuning issues for the NetWorker
backup devices within the Windows environment. For a general discussion of
how device issues affect NetWorker software performance, see "Backup
Devices" on page 44.
How to Test Device Performance
To test device input/output, see the bigasm program test described in "How to
Test Device Performance with bigasm" on page 48.
Tuning Device Performance
Most tape drives come with hardware data compression enabled by default.
When compression is enabled, device performance and media capacity can
double.
Hardware data compression is controlled by the NSR_NO_HW_COMPRESS
environment variable. When you set this environment variable to Yes, data is
not compressed by the hardware before it is written to media.
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Notes:
•
•
For data that is already compressed before it reaches the device,
additional compression might increase the size of the data. If the data
comes to the device already compressed, you can disable compression on
the storage device.
When you change the name of an existing variable, Windows NT treats it
as a new variable and does not overwrite or delete original variable.
How to Tune Device Performance on Windows NT
To tune the hardware compression system variable on a Windows NT
computer:
1. Select Start>Settings>Control Panel.
2. Double-click the System icon and click the Environment tab.
3. Review the variables and values listed in the System Variables list box.
Depending on whether the NSR_NO_HW_COMPRESS variable already
exists or not, follow the appropriate step:
–
5
–
If the NSR_NO_HW_COMPRESS variable is already listed, and you
simply want to change its value, select it. The variable name and its
value appear in the Variable and Value text boxes.
a. Change its value to Yes.
b. Click Set to confirm the change.
The updated value of the NSR_NO_HW_COMPRESS variable is
reflected in the System Variables list box.
If the NSR_NO_HW_COMPRESS variable is not listed, you need to
create it.
a. Select any variable so that its name and value are displayed in the
Variable and Value text boxes.
b. Change the existing variable name to
NSR_NO_HW_COMPRESS.
c. Enter the value yes.
d. Click Set to confirm the new variable.
The new variable and its value are reflected in the System Variables
list box, and the original one you selected remains unchanged.
4. Click OK when you have completed adding or modifying the
NSR_NO_HW_COMPRESS variable and/or its value.
5. Restart the NetWorker server.
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To see the device compression setting, enter the following at the command
line:
mt -f \\.\Tape0 stat
In the output of a device with compression enabled, the following appears:
Compress Enabled
How to Tune Device Performance on Windows 2000
To tune the hardware compression system variable:
1. Select Start>Settings>Control Panel.
2. Double-click the System icon.
3. Select the Advanced tab and click Environment Variables.
4. Review the variables and values listed in the System Variables list box.
Depending on whether the NSR_NO_HW_COMPRESS variable already
exists or not, follow the appropriate step:
–
–
If the NSR_NO_HW_COMPRESS variable is already listed, and you
simply want to change its value, select it. The variable name and its
value appear in the Variable and Value text boxes.
a. Change its value to Yes.
b. Click OK to confirm the change.
The updated value of the NSR_NO_HW_COMPRESS variable is
reflected in the System Variables list box.
If the NSR_NO_HW_COMPRESS variable is not listed, you need to
create it.
a. Click New.
b. Enter the variable name NSR_NO_HW_COMPRESS
c. Enter the value Yes.
d. Click OK.
5. When you have completed adding or modifying the
NSR_NO_HW_COMPRESS variable and/or its value, click OK.
6. Restart the NetWorker server.
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Windows Software
To see the device compression setting, enter the following on the command
line:
mt -f \\.\Tape0 stat
In the output of a device with compression enabled, the following appears:
Compress Enabled
Windows Software
The following variables affect the overall Windows operating system
performance and the speed of backup:
•
•
5
•
90
Filesystem overhead
Filesystem input/output (I/O) can degrade I/O performance. If you
integrate logical volume managers with the filesystem, you can increase
disk performance and add a host of other features to improve
manageability of large filesystems. Also, depending on the level of RAID
(Redundant Array of Independent Disks) you implement, RAID can
improve or adversely affect backup performance.
Server memory usage setting
You can set server memory use to be optimized for the following:
– Small number of clients
– Large number of clients
– Fileserver
– Domain controller
For more information, see "Memory Performance Evaluation Methods" on
page 75.
Page file size
You can adjust the size and location of the virtual memory file (pagefile.sys)
on the local disks. For more information, see "Memory Performance
Evaluation Methods" on page 75.
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Chapter 5: Testing and Tuning on Windows
Recoveries
Recovery performance can fluctuate based on a variety of issues, including
network traffic, bottlenecks, and file sizes. One method of recovering data
efficiently is to start multiple recover commands simultaneously through the
save set recovery method.
For example, you can start three different save set recover programs instead of
one save set recover program with three save sets. Separate recover programs
provide the maximum parallelism possible given the number of daemons and
the actual volume and save set layout.
Important: If multiple, simultaneous recover programs are being run from the
same tape, do not let the tape mount and start until all recoveries are ready. If
the tape is used before all recoveries are ready, the tape will be read through
multiple times and recovery performance will be slower, rather than faster.
How to Perform Multiple, Simultaneous Recoveries
To perform multiple recoveries:
1. Open one NetWorker User program for each save set that needs to be
recovered.
2. In each window, select the save set to be recovered, but do not start the
recovery process.
3. Once all three save sets have been selected in their respective window,
execute each recovery consecutively.
4. Measure the time it takes to recover all three save sets.
5. Once the recoveries are finished, perform another recovery with all three
save sets in the same recover request.
6. Compare the time needed for the multiple recover requests to the time
needed for the single recover request.
The multiple recoveries should have finished before the single recovery of
multiple save sets. If the single recovery completed faster, the tape may have
been mounted before all recoveries could start or the computer is CPU-bound
rather than I/O-bound. To determine the cause of the bottlenecks, use the
performance and activity monitoring tools available with the operating
system.
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Appendix A: Troubleshooting
RPC Error Messages
When trying to connect to the NetWorker server, you may encounter the
following error messages:
Error: 'save: RPC error: Remote system error'
Error: 'save: Cannot open save session'
Problem
When under stress, the current RPC implementation can only handle a small
burst of connection requests. The server services only one connection request
each time it goes through the select() loop. When the server is busy serving
other connections, it takes more time to do one select() loop, and the server
services a lower number of connection requests per second.
For example, there are 10 clients calling the service, and each client takes 10ms
to service. It takes 200ms to go around the select loop, and it can only service
10 connection requests per second.
In some customer environments, over 400 clients could be attempting to
connect to the same server over a short period of time. If the server is under
stress and can only handle 10 connection request per second, it will not be able
to handle the burst of 400 connection requests. The server can only queue up
twenty requests. The connection requests that are not queued up may attempt
to retry, or they may fail with multiple RPC errors.
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Solution
Solution
To avoid this problem, increase the SOMAXCONN parameter, a kernel
parameter that governs the maximum number of unaccepted socket
connections that can be waiting in queue. It is also referred to as the listen()
queue limit. When NetWorker (NSRD) starts, it requests a listen() queue of 200.
Ensure that the value for SOMAXCONN is set to 200 or higher. This parameter
must be set before NSRD starts.
The following are examples of setting the SOMAXCONN parameter on
various platforms:
•
•
•
•
A
94
For Solaris, enter the following commands:
/usr/sbin/ndd -set /dev/tcp tcp_conn_req_max_q 1024
where the q queue holds sockets awaiting an accept() call.
/usr/sbin/ndd -set /dev/tcp tcp_conn_req_max_q0 2048
where the q0 queue contains half-open sockets.
For Tru64 UNIX:
a. Enter the following command:
/sbin/sysconfig -r socket sominconn=65535
The value of sominconn determines how many simultaneous
incoming SYN packets can be handled by the system.
b. /sbin/sysconfig -r socket somaxconn=65535
The value of somaxconn sets the maximum number of pending TCP
connections.
For HP-UX, enter the following commands:
/usr/sbin/ndd -set /dev/tcp tcp_syn_rcvd_max 1024
/usr/sbin/ndd -set /dev/tcp tcp_conn_request_max 200
For Linux, enter the following command to increase the size of the socket
queue (effectively, q0):
/sbin/sysctl -w net.ipv4.tcp_max_syn_backlog=1280
Legato NetWorker
Performance Tuning Guide
Appendix A: Troubleshooting
Troubleshooting Target Sessions
The Target Sessions attribute sets the number of backup sessions accepted by
an active device. The Target Sessions attribute is configured in the Device
resource, and a different value can be specified for each device.
If the Target Session value is set too high, the performance of the backup does
not always improve. For example, suppose the Parallelism attribute is set to 16,
which means the NetWorker server can handle up to 16 streams of data from
the NetWorker clients. If the Target Session attribute for each device is set to
16, then each device can also handle 16 streams. In this case, the 16 data
streams from the clients may be sent to the same device, since each device can
handle 16 streams. No benefit is gained by using the Target Sessions attribute.
To optimize device usage, set the Target Session attribute to less than the
Parallelism attribute so more than one device is selected for multiple backup
streams.
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Glossary
This glossary contains terms and definitions related to this manual. Most of the
terms are specific to Legato NetWorker products.
1-9
Intermediate backup levels. Each number represents a
backup level. Lower levels back up more files.
Administrators
group
Windows NT user group whose members have all the
rights and abilities of users in other groups, plus the
ability to create and manage all the users and groups in the
domain. Only members of the Administrators group can
modify Windows NT OS files, maintain the built-in
groups, and grant additional rights to groups.
annotation
A comment that you associate with an archive save set, to
help identify that data later on. Annotations are stored in
the media index for ease of searching and are limited to
1024 characters.
Application-Specific
Module (ASM)
A program that, when used in a directive, specifies the
way a set of files or directories is to be backed up and
recovered.
archive
The process by which NetWorker backs up directories or
files to an archive volume and then optionally deletes
them to free up disk space.
archive clone pool
A volume pool composed exclusively of archive clone
save sets.
archive pool
A volume pool composed exclusively of archive save sets.
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Glossary
Glossary
98
archive volume
A tape or other storage medium used for NetWorker
archives, as opposed to a backup volume.
ASM
See Application-Specific Module (ASM).
autochanger
A mechanism that uses a robotic arm to move media
among various components located in a device including
slots, media drives, media access ports, and transports.
Autochangers automate media loading and mounting
functions during backups and recovers.
Backup Operators
group
A Windows NT group whose members have the capability
of logging on to a domain from a workstation or a server,
backing it up, and restoring the data. Backup Operators
also can shut down servers or workstations.
backup volume
Backup media, such as magnetic tape or optical disk.
bootstrap
Information that includes the server index, media index,
and configuration files needed for recovering NetWorker
after a disk crash.
browse policy
The policy that determines how long entries for the files
remain in the online file index.
carousel
A tray or tape cartridge that holds multiple backup
volumes.
client
A computer that accesses the NetWorker server to back up
or recover files. Clients may be workstations, PCs, or
fileservers.
clone
The process by which NetWorker makes an exact copy of
saved data (save sets). NetWorker can clone individual
save sets or the entire contents of a backup volume.
clone volume
A duplicated volume. NetWorker can track four types of
volumes: backup, archive, backup clone, and archive
clone. Save sets of different types may not be intermixed
on one volume.
command line
The shell prompt, where you enter commands.
Legato NetWorker
Performance Tuning Guide
Glossary
A NetWorker directive used for compressing and
decompressing files.
device
The backup device (tape drive, optical drive, or
autochanger) connected to the NetWorker server; used for
backing up and recovering client files.
directive
An instruction directing NetWorker to take special actions
on a given set of files.
enabler codes
Special codes provided by Legato that allow you to run
the NetWorker software product.
file index
A database of information maintained by NetWorker that
tracks every file or filesystem backed up.
fileserver
A computer with disks that provides services to other
computers on the network.
filesystem
1. A file tree on a specific disk partition or other mount
point. 2. The entire set of all files. 3. A method of storing
files.
full (f)
A backup level in which all files are backed up, regardless
of when they last changed.
grooming
The process of removing files after a successful archive.
group
A client or group of clients that starts backing up its files at
a designated time.
heterogeneous
networks
Networks with systems of different platforms that interact
meaningfully across the network.
himt
A choice in the Devices window; represents half-inch
magnetic tape.
incremental (i)
A backup level in which only files that have changed since
the last backup are backed up.
interoperability
The ability of software and hardware on multiple
computers from multiple vendors to communicate
meaningfully.
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Glossary
compressasm
Glossary
Glossary
100
level (1-9)
A backup level that backs up files that have changed since
the last backup of any lower level.
media
Magnetic tape or optical disks used to back up files.
media index
A database of information maintained by NetWorker that
tracks every backup volume.
media manager
The NetWorker component that tracks save sets to backup
volumes.
NetWorker
A Legato network-based software product to back up and
recover filesystems.
NetWorker client
A computer that can access the backup and recover
services from a NetWorker server.
NetWorker server
The computer on a network running the NetWorker
software, containing the online indexes and providing
backup and recover services to the clients on the same
network.
notice
A response to a NetWorker event.
nsrhost
The logical hostname of the computer that is the NetWorker
server.
online indexes
The databases located on the server that contain all the
information pertaining to the client backups and backup
volumes.
operator
The person who monitors the server status, loads backup
volumes into the server devices, and otherwise executes
day-to-day tasks using NetWorker.
override
A backup level that takes place instead of the scheduled
one.
pathname
Instructions for accessing a file. An absolute pathname tells
you how to find a file beginning at the root directory and
working down the directory tree. A relative pathname tells
you how to find the file starting where you are now.
Legato NetWorker
Performance Tuning Guide
Glossary
Existing selections or configurations for different
NetWorker features.
print
Send data to a printer.
qic
A choice in the Devices window; represents quarter-inch
cartridge tape.
recover
The NetWorker command used to browse the server index
and to recover files from a backup volume to a clients disk.
recycle
A volume whose data has passed both its browse and
retention policies and is available for relabeling.
Registry
A database of configuration information central to
Windows NT operations. The overall effect centralizes all
Windows NT settings and provides security and control
over system, security, and user account settings.
retention policy
A NetWorker policy that determines how long entries will
be retained in the media database and thus be recoverable.
retrieval
The process of locating and copying back files and
directories that NetWorker has archived.
save
The NetWorker command that backs up client files to
backup volumes and makes data entries in the online
index.
save set
A set of files or a filesystem backed up onto backup media
using NetWorker.
save set ID
An internal identification number assigned to a save set by
NetWorker.
scanner
The NetWorker command used to read a backup volume
when the online indexes are no longer available.
server
The computer on a network running the NetWorker
software, containing the online indexes and providing
backup and recover services to the clients on a network.
shell prompt
A cue for input in a shell window where you enter a
command.
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Glossary
preconfigured
Glossary
A backup level in which files are skipped and not backed
up.
stand-alone device
A backup device that contains a single drive for backing
up data. Stand-alone devices cannot store or automatically
load backup volumes.
system administrator
The person normally responsible for installing,
configuring, and maintaining NetWorker.
user
A person who can use NetWorker from his or her
workstation to back up and recover files.
volume
Backup media, such as magnetic tape or optical disk.
volume ID
The internal identification assigned to a backup volume by
NetWorker.
volume name
The name you assign to a backup volume when it is
labeled.
volume pool
A feature that allows you to sort backup data to selected
volumes. A volume pool contains a collection of backup
volumes to which specific data has been backed up.
Glossary
skip (s)
102
Legato NetWorker
Performance Tuning Guide
Index
A
absolute pathnames 37
ansrd service 20–21
application specific module See ASMs
ASMs 34–36
authentication
nsrexecd 21
B
backplane
transfer rate 40
backup cycle 20
backup devices See devices
backups
balancing disks and devices 43
group 21
RAID performance 90
remote 26
removing oldest 20
scheduled 21
splitting 43–44
bandwidth
increased performance 39–40, 43
limitations 17, 44, 51
benchmarks 32
devices 58
disks 54
bigasm module 41, 48, 59, 87
options 48
block device activity
monitoring 61
bootstrap file 23
boundaries
crossing 37
browse policies 51
buffer activity
monitoring 60
Business Edition
advantages 15
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Performance Tuning Guide
features
options
16
16
C
client file index 19, 21–22
consistency check 20
nsrindexd 20
Client Priority attribute 22
clients
backups
ad-hoc 21
groups 22
multiple 20
scheduled 21
compression 44
groups 20–22
backups 22
high transfer rate 44
parallelism 41, 44
programs 21
remote
backup 27
recover 27
services 21
compare mode
uasm program 34
compression 44, 87–89
built-in device 49
of data 33
configuration
file type devices 50
of NetWorker 25
conflicting filenames
options 38
suffix 37–38
contention, disk 51
count value 45
CPU 39, 43, 79
evaluating problems 81
performance 81
testing 39, 79
103
Index
D-H
Index
utilization
tuning 39
62
D
data
compression 44, 49
recovery by NetWorker 24
remote client
backup 27
recover 27
streaming 49
databases
immediate save, using 27
defragmentation 38
devices 43–44, 87–89
balancing backup load 43
benchmarks, evaluating 58
compression, built-in 49
data streaming 49
file type 49–50
high-speed 27
input/output 48
load balancing 49
magnetic tape 45
multiple 28
performance 45, 48
RAID 51
silos 28–29
support 20
testing 44–45, 48, 58–60, 70–71
multiple 58, 60
NetWorker running 59–60
tuning 48
write speed 44, 48, 57–60, 70–71
See also high-speed devices
df command 55–57
directive
bigasm module 48
files 34
ignoring save 36
disk seek reduction 38
disks 33
balancing backup load 43
benchmarks 55
contention 51
data
104
compression 33
fragmentation 33
evaluating problems 72
file type device usage 50
performance 54, 70, 72
read speed 44, 54–55, 70
testing 33, 35, 54–56
multiple 55–56
NetWorker running 56
tuning 38, 72, 90
E
edition
Business 15
Network 15
Power 16
Workgroup 15
enhancements, RPC 26–27
evaluating
benchmarks 54, 58
CPU 81
disks 72
memory 75
F
file type devices 49–50
configuration 50
disks
contention 51
usage 50
RAID 51
files
defragmentation 38
filesystem boundaries
crossing 37
fragmentation 33
H
high-speed devices
See also devices
27, 43
Legato NetWorker
Performance Tuning Guide
Index
I-O
I
26–29
L
load balancing 49
local backup and recover
logs, savegrp executions
26, 28
23
M
media database 19–21
nsrim 20
nsrmmd service 22
memory 39, 42, 73–74
evaluating problems 75
performance 75–76, 78
physical allocation 77
server, usage 90
tuning 76, 78, 90
virtual 76, 90
mt program 45
commands 46–47
count value 45
exit status 45
multiple recoveries 63, 91
multiplexing 20–21, 41–43
N
network
bandwidth 51
input/output 51
load 51
path 51
performance 51
tuning 52
Legato NetWorker
Performance Tuning Guide
Index
I/O See input/output
immediate save and recover
input/output
devices 48
server
backplane 40
SCSI bandwidth 40
Windows filesystem 90
Network Edition
advantages 15
features 16
options 16
NetWorker
backups, how done 21
client file index 19–22
configurations 25
maintaining configuration 20
media database 19–22
older servers 36
overview 19
programs 19
recovery, data 24
services 19
settings 41
testing while running 59–60
nsrck service 20, 22
nsrd service 20–22, 24
ansrd 20
nsrck 20
nsrim 20
nsrexecd service 21–22
nsrim service 20
nsrindexd service 20–22
nsrmmd service 20–22, 24, 29
writing data 22
nsrmmdbd service 20, 22, 24
O
options
bigasm 48
-i 38
mode
recover 37
save 36
mt command 46
overwrite response 38
physical memory allocation 77
proto 36
supported by NetWorker editions
uasm 35
16
105
Index
P-R
Index
P
parallelism 22, 41–42
client 41, 44
performance
backups 90
benchmarks
devices 58
disks 54
CPU 79, 81
devices 17, 44–45, 48, 57–60, 70–71, 87
disks 54, 56, 70, 72, 90
evaluating
CPU 81
disks 72
memory 75
factors
hardware 17
network 17
software 18
file type device 49–50
filesystem overhead 90
hardware 17
input/output, server 82
memory 73, 75–76, 78
tuning 90
network 17, 44, 51
tuning 52
overview 17
remote backups 26
RPC enhancements 27
server 17
input/output 82
silos 28
software 18
staging 49–50
stripe sets 38
testing
CPU 79
devices 57–60, 70–71, 87
disks 54–56, 70, 72
memory 73–74
overview 32
server input/output 82
tuning
CPUs 39
devices 48, 87–89
106
disks 38, 72, 90
file type devices 50
memory 76, 78, 90
network hardware 52
overview 32
settings 42
UNIX-based, overview 53–54
Windows
overview 65
software 90
Performance Monitor
CPU 79, 81
disks 70–72
memory 73–76, 78
overview 65
remote monitoring 68
on Windows 2000 69
on Windows NT 68
server input/output 82
starting
on Windows 2000 67
on Windows NT 66
physical disks See disks
policies
browse 51
retention 51
pools 22, 43
Power Edition
advantages 16
features 16
options 16
programs
backup 24
proto option 36
R
RAID 90
read speed, disks
benchmarks 54–55
testing 33, 35, 44, 54–56
recover mode
uasm program 34
recover program 20–21, 24
recoveries
multiple 63, 91
overview 25
Legato NetWorker
Performance Tuning Guide
Index
S-T
S
save directives
ignoring 36
save mode
uasm program 34
save program 20–22
nsrindexd 20
save sets
backup information 21
multiplexing 20, 43
parallelism 22
staging 49–51
savefs program 21–22
savegrp program 20–23
parallelism 22
SCSI bandwidth 40
server
CPU 43
hardware 33
input/output 40
backplane 40
SCSI bandwidth 40
memory 42
multiplexing 41–42
parallelism 41–42
target sessions 41–43
server input/output 82
service
ansrd 20
backup 24
nsrck 20
nsrd 20
nsrim 20
nsrindexd 20
nsrmmd 20, 22
nsrmmdbd 20
settings
tuning 42
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Performance Tuning Guide
20
silos 28–29
single file recovery 21
somaxconn 94
SOMAXCONN parameter 94
sominconn 94
staging 49–51
STLI call 29
storage devices See devices
storage nodes 28
with file type devices 50
stripe sets 38
subkey entry, Registry 85
suffix for conflicting filenames 37
symbolic links
limitations 37
System Activity Reporter 60
monitoring
block device activity 61
buffer activity 60
testing CPU utilization 62
system requirements 32
Index
single file 21
Registry, Windows 84–85
retention policies 51
RPC
enhancements 26–27
save and recover program
RPC error message 93
T
target sessions 41–43, 95
TCP/IP 23, 26
testing
controlled 32
CPU 79
devices 44, 57–60, 87
disks 33, 35, 55–56, 70–71
from another computer 68
input/output 82
less controlled 32
memory 73–74
overview 32
See also performance
tuning
backup load 43–44
clients 44
compression 44
CPUs 39
devices 48, 87
disks 38, 43, 72
file type devices 50
memory 76, 78
network hardware 52
107
Index
Index
U-W
overview 32
parallelism 42
client 44
server 42
recoveries 43
See also performance
settings 42–44
target sessions 42
Windows software 90
U
uasm module 33, 41
syntax 33
uasm program 56
byte count mode 36
compare mode 34
options 35
verbose mode 35
recover mode 34
options 37
save mode 34
options 36
UNIX-based performance
devices 57, 59
benchmarks 58
testing 57–58, 60
disks
benchmarks 54–55
testing 54–56
testing, overview 53–54
memory 73–76, 78, 90
counter values 75
operating system 90
Registry
modification 84
subkey entry 85
server input/output 82
testing, overview 65
Workgroup Edition
advantages 15
features 16
options 16
write speed, devices
benchmarks 58
measuring 44
testing 57–60, 70–71
V
virtual memory 39
volumes
dividing save sets
pools 22, 43
43
W
Windows-based performance
CPU 79, 81
devices 70–71, 87–89
disks 70, 72
filesystem overhead 90
108
Legato NetWorker
Performance Tuning Guide
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