iSCSI for TL-Series Tape Libraries

iSCSI for
TL-Series
Tape Libraries
Direct Attach a Dell
PowerVault TL2000 /
TL4000 to an iSCSI SAN
By Michael Linane, Jo Ann Varble, Neil Ozarkar , Curt
Krempin and Charles Butler
Dell │ Storage Product Group
www.dell.com/TLseries
November 2008
CONTENTS
EXECUTIVE SUMMARY
3
INTRODUCTION
3
iSCSI SAN SOLUTIONS
4
STEP-BY-STEP
4
NETWORK SETTINGS
6
STORAGE TARGETS : TL2000 / TL4000
9
CONFIGURING AN MD3000i
9
BACKUP EXEC 12 FOR WINDOWS SERVER INSTALLATION
10
SUMMARY
10
FIGURES
FIGURE 1 : Microsoft’s iSCSI Initiator
5
FIGURE 2 : IP Address
6
FIGURE 3 : iSCSI Targets
6
FIGURE 4 : Target Log On
6
FIGURE 5 : Network Connections
7
FIGURE 6 : Local Area Connection Properties
7
FIGURE 7 : IP Properties
7
FIGURE 8 : Select Network Adapter
8
FIGURE 9 : Jumbo Frames Settings
8
FIGURE 10 : PowerConnect
9
FIGURE 11 : General Settings
9
FIGURE 12 : Copy Files
9
FIGURE 13 : TL2000 / TL4000 1Gb iSCSI to SAS Bridge
10
FIGURE 14 : Set IP Address and Frame Size
10
FIGURE 15 : Configure iSCSI Settings
11
FIGURE 16 : Configure Host Ports
11
FIGURE 17 : Environment Check Screen
12
FIGURE 18 : Licensing Screen
13
CONTENTS
FIGURE 19 : Options and Agents Screen
13
FIGURE 20 : Backup Job Selections Screen
15
FIGURE 21 : Device and Media Screen
15
FIGURE 22 : Backup Jobs General Settings Screen
16
FIGURE 23 : Backup Jobs Schedule Screen
16
FIGURE 24 : Job Monitor Screen
17
FOR FURTHER INFORMATION AND DISCUSSION
PowerSolutions :
iSCSI for TL-Series Tape Libraries
SECTION 1
EXECUTIVE SUMMARY
To supplement the growth in iSCSI SANs, Dell has introduced an iSCSI-to-SAS bridge card
for the TL-series of tape libraries (Dell PowerVault TL2000 & TL4000). This offering allows a
customer to directly attach a tape backup target to their iSCSI 1Gb Ethernet SAN with little to
no degradation in transfer speed, 90 MB/s in most cases. The following white paper explores
the setup, configuration and considerations associated with implementing this solution.
SECTION 2
INTRODUCTION
This white paper assumes a typical SMB environment with 5-10 Windows servers as an example of how to implement an iSCSI tape backup solution. The example SMB network incorporates an iSCSI 1GbE SAN containing disk (primary/secondary storage) and tape (backup &
archive) elements. The intent is to provide insight into the purchase decisions and setup considerations regarding the ISVs, server initiators, networks and storage target. Please note,
there are many different variations – this is just one of them. The primary focus will center
around the set up and configuration of an iSCSI network and perform back-ups to it.
In our example network, at least one server will need to be attached to the backup elements.
Depending on your backup window constraints and availability of existing servers during that
time, one of those might even be used. In general, the smaller the backup window, the greater
the number of servers that are required to be connected to the backup elements. In the example here, the assumption is there are no backup window constraints (can backup overnight)
and there is one server available (and necessary) to be connected to the disk and tape device.
Server
Server
Server
Server
LAN
Back-up Server
iSCSI SAN
MD3000i
TL2000/TL4000
with
TL24iSCSIxSAS
Now that the example network topology has been defined, let’s explore the benefits of an
iSCSI SAN as compared to alternatives.
Why might you choose iSCSI?
Cost – iSCSI networks typically cost less to acquire and maintain than the equivalent Fibre
Channel version
Ease of Installation – iSCSI networks only require the same basic networking skills used in
maintaining a standard IP network (cf., Fibre Channel)
Scalability – One of the advantages over direct attach is the ability for ready expansion as
business needs grow.
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iSCSI for TL-Series Tape Libraries
SECTION 3
iSCSI SAN SOLUTIONS
To complement the Dell PowerVault MD3000i and Dell EqualLogic & EMC line of iSCSI interface disk storage systems, Dell has introduced an iSCSI-to-SAS Bridge Card for the Dell
PowerVault TL2000 & TL4000 tape libraries. This card, when inserted into a TL-Series tape
library, acts as an iSCSI target and provides SAS connectivity for LTO4, LTO4HH and
LTO3HH tape drives.
Best Practices: Oversubscription of the network switches can lead to many of the
“performance” concerns often voiced about iSCSI networks. Using a dedicated, switched 1GbE
switch such as the Dell PowerConnect 62XX or 54XX for iSCSI traffic is recommended. Should
this prove unfeasible, deploying a PowerConnect 54XX iSCSI-optimized switch for combined
traffic is recommended. It will detect iSCSI traffic and raise its Level of Service – in essence,
providing more bandwidth to the iSCSI traffic.
Best Practices: In most applications, exposing an iSCSI SAN to the internet can result in a
security vulnerability and should be avoided if possible. While iSCSI does have some security
features integrated into its specification (e.g., CHAP), it is typically a user-selectable feature
and is not as robust as some other systems. Additionally, unless IPsec is implemented and
enabled, data in-flight is transmitted “in the clear.” Use of private, dedicated networks is
strongly encouraged.
SECTION 4
STEP-BY-STEP SETUP
Servers connected to the iSCSI SAN will require an iSCSI initiator. Since most servers are
Windows-based, Microsoft’s iSCSI Initiator is a cost effective solution, available as a free
download: http://www.microsoft.com/downloads/details.aspx?FamilyID=12cb3c1a-15d6-4585b385-befd1319f825&DisplayLang=en. Once installed, the set-up and use is straight-forward.
Figure 1 : Microsoft’s iSCSI Initiator
The important consideration on this screen is the use of CHAP (Challenge Handshake Authentication Protocol). This is the main security apparatus in iSCSI. If your iSCSI SAN is visible to
the external internet, it is highly recommended to enable this feature. Even with the availability
of CHAP, it is still recommended to keep the iSCSI SAN private and not visible to the outside
world.
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iSCSI for TL-Series Tape Libraries
On the Discovery tab, the IP address of the iSCSI target needs to be entered.
Figure 2 : IP Address
On the Targets tab, the available iSCSI targets are displayed and available for log-on.
Figure 3 : iSCSI Targets
Figure 4 : Target Log On
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iSCSI for TL-Series Tape Libraries
One drawback to Microsoft’s iSCSI Initiator is that it does use the server cycles to create the
iSCSI packets. This, in combination with other processor-intensive operations (like back-up
jobs), can reduce the performance and throughput of the server and associated back-up jobs.
Alternatives would include the use of a HW iSCSI HBA or other off-load engine. This would
remove the SCSI-to-iSCSI conversion workload from the server’s microprocessor and likely
result in overall improved performance.
SECTION 5
NETWORK SETTINGS
A dedicated NIC port and static addresses is highly recommended. Configuration is outlined
below:
Figure 5 : Network
Connections
Figure 6 : Local Area
Connection Properties
Figure 7 : IP Properties
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iSCSI for TL-Series Tape Libraries
Use of Jumbo Frames – Although somewhat controversial, in a clean network, jumbo frames
can significantly improve the performance of back-up jobs. However, if the network is subject
to dropping packets (e.g., high traffic), the performance could degrade due to resending the
larger packets. The network outlined in this article would benefit from using jumbo frames and
they are enabled as seen below:
In Windows 2003 Storage Server:
1.
2.
3.
4.
Open Computer Manager
Open Device Manager
Open Network Adapter
Select Adapter running the iSCSI Initiator (such as Microsoft iSCSI Initiator)
Figure 8 : Select Network Adapter
5.
6.
7.
Right click and open Properties
Open Advanced
Select Jumbo Frames and 9014 bytes or larger.
Figure 9 : Jumbo Frames Settings
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iSCSI for TL-Series Tape Libraries
For Jumbo frames to function properly, the entire path between the back-up server to the storage target needs to enable jumbo frames. Assuming a PowerConnect 5448 switch, this is done
as follows:
Figure 10 :
PowerConnect
5448
Select Advanced Settings and then General Settings.
Figure 11 :
General
Settings
The settings will then need to be saved to the Start-up Configuration and the switch rebooted.
Expand the System tree on the left pane, select Files, then Copy Files.
Figure 12 :
Copy Files
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iSCSI for TL-Series Tape Libraries
SECTION 5
STORAGE TARGETS : TL2000 / TL4000
Set-up of the TL2000/TL4000 with iSCS-to-SAS bridge card follows the same process:
Figure 13 : TL2000 / TL4000 1Gb iSCSI to SAS Bridge
Select Connections and set the IP address and frame size for the port(s).
Figure 14 : Set IP Address and Frame Size
SECTION 6
CONFIGURING AN MD3000i
Assuming a Dell PowerVault MD3000i, an iSCS disk array, is connect to the example network,
the initial configuration would require physically installing & powering on the unit and then installing and running Modular Disk Storage Manager (MDSM) on the host computer. After installation of MDSM has been completed on the host computer, the disk array must be discovered by the host. The default management IP addresses for the MD3000i are
192.168.128.101 for Controller 0 and 192.168.128.101 for Controller 1. After these addresses
are used to establish connectivity to the unit, the remaining steps include setting up disk
groups, creating virtual disks, and assigning LUNs (Logical Unit Numbers) to the virtual disks.
More information on this can be found in the documentation for the MD3000i on
www.support.dell.com. To configure the iSCSI settings, go to the iSCSI tab in MDSM (Figure
15). To configure the host ports, select “Configure iSCSI Host Ports” (Figure 16). There are 2
Host Ports on each controller, and they are, by default, assigned IP addresses
192.168.130.101-102 and 192.168.131.101-102. The Advanced button will enable the user to
change settings for VLAN support, Ethernet priority, TCP listening port, and Ethernet Jumbo
frames. Enable Jumbo Frames and select 9000 for the Bytes/frame size.
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iSCSI for TL-Series Tape Libraries
Figure 15 : Configure iSCSI Settings
Figure 16 : Configure Host Ports
Note: If Jumbo Frames are enabled, they must be enabled for all devices across the network
(including the host, target, and any switches or routers in between). Jumbo frame sizes will
allow for greater packet payloads and lower overhead traffic, resulting in likely performance
increases.
Note: If the ICMP “PING” command will be used to network connectivity, the “Enable ICMP
PING responses” checkbox must be checked.
After these settings have been enabled, the Windows iSCSI initiator on the host computer can
be used to perform discovery of the MD3000i target. After the iSCSI initiator on the host has
discovered the MD3000i, go to the “Configure” tab on the MDSM and select “Configure Host
Access - Manual”. Enter the host name into the configuration, select the operating system,
and select “Next”. This will guide the user to a screen to select iSCSI initiators. If a known
initiator is displayed, highlight it, click “Add”, and then “Next”. Otherwise, select “New” and
enter the iSCSI initiator name and select “Next”. After selecting whether the host is on a Microsoft cluster, click “Finish”.
If CHAP is going to be used in the iSCSI network, it can be enabled at this point under the
“iSCSI” tab under the “Change Target Authentication” and “Enter Manual Authentication Permissions” selections in MDSM.
SECTION 7
BACKUP EXEC 12 FOR WINDOWS SERVER INSTALLATION
Symantec offers a good backup solution for SAN based environments and can easily be configured for iSCSI. Symantec recommends that you have connected all of the I/O controllers,
tape hardware devices, and other storage devices to the system where Backup Exec will be
installed before beginning the Backup Exec installation. Before installing Backup Exec 12 for
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iSCSI for TL-Series Tape Libraries
Windows Servers it is recommended that you run the Backup Exec Environment Check on the
system which is planned to contain the Backup Exec installation.
The Backup Exec Environment Check is included with the installation media. The Environment
Check analyzes the computer to make sure that the installation process can complete. If
Backup Exec finds configuration issues that can be fixed during the installation, or that may
prevent the installation, warnings will appear. Although the Environment Check runs automatically during installation, it is recommended that it be run manually before installing Backup
Exec or before starting to back up data with Backup Exec.
Figure 17: Environment Check Screen
Once the Environment Check has passed, the Backup Exec installation can begin by selecting
“Start the Backup Exec Installation” found on the installation CD Browser. The Installation
Wizard will walk through initial configuration settings about the installation and then arrive at
the licensing screen. On this screen, input a license key for Backup Exec for Windows and
each Backup Exec Agent or Option that is required for your environment. The license key
information can be found on the Software license card that comes with your CD kit at time of
purchase.
For our example network, the following Symantec Backup Exec packages would be needed:
•
•
•
Symantec Backup Exec Multi-Server Suite which provides a complete backup solution for
one Windows backup server and agents to perform scheduled and continuous protection
of 3 Windows servers.
Symantec Backup Exec Application Protection Add-on Pack which provides complete
protection for two applications.
Symantec Backup Exec Library Expansion Add-on Pack which allows for the use of two
additional tape drives in a tape library with an existing Backup Exec 12.0 for Windows
Media Server.
The backup environment easily scales with your backup needs. Additional Backup Servers
can be added with the purchase of new Symantec Backup Exec Multi-Server Suites. Symantec Backup Exec Windows Remote Server Add-on Pack provides the ability to protect two
additional remote Windows Servers and twenty Windows desktop and laptops. NetWare,
Linux and UNIX Servers can also be protected with the addition of Symantec Backup Exec
NetWare, Linux & UNIX Remote Server Add-on Pack. Symantec Exec can also scale to a
SAN environment with the addition of the Symantec Backup Exec SAN-based Server Suite.
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iSCSI for TL-Series Tape Libraries
Figure 18 : Licensing Screen
Once all of the license keys have been entered, Backup Exec will display the list of agents and
options that will be installed on the system. Select any additional features as required and
continue with the installation.
Figure 19 : Options and Agents Screen
The installation wizard will continue and determine the installation settings for the following
items:
•
•
Determining the location for SQL Express used as the Backup Exec database
Selection of Symantec device drivers (recommended) or 3rd party device drivers for use
with the tape hardware
Once the wizard completes, Backup Exec will be installed on the system.
The next step is to install the Remote Agent for Windows Systems on the remote systems that
are being protected. The Remote Agent is a system service that runs on remote Windows
servers and workstations. The Remote Agent provides faster backup processing by locally
performing tasks that in typical backup technologies require extensive network interaction. The
Remote Agent processes backup data into a continuous stream that the media server then
processes as a single task. This method provides better data transfer rates over traditional
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iSCSI for TL-Series Tape Libraries
technologies, which require multiple requests and acknowledgments between the media server
and the remote server.
1.
2.
3.
4.
5.
7.
8.
9.
10.
11.
12.
13.
14.
15.
On the navigation bar, click the arrow next to Backup.
Click New Backup Job.
On the View by Resource tab, right-click the computer that you want to install the Remote
Agent and the AOFO to, and then click Install Remote Agent/Advanced Open File Option.
On the Installation wizard, click Next.
On the Remote Computer Logon Credentials panel, complete the options as follows:
Username, password, domain
Click OK.
In the Features pane, click the options that you want to install, and then click Finish.
When the Publish Remote Agent Information dialog box appears, enter the appropriate
information to publish the remote agent to the media server
Click OK.
Click Next.
Read the installation review, and then click Install.
The Remote Installation Status dialog box appears, and selected options are installed on
the remote computer.
When the installation status indicates that the reboot is complete, right-click the server
name again, and click View Install Log or View Push Log.
When the installation is complete, click Next, and then click Finish.
Backup Strategy
Now that the installation is complete, it is time to determine what backup strategy will meet
your needs. The first step in determining an appropriate backup strategy is defining the
backup windows for each system and identifying the amount of data to be protected. With
Backup Exec, there are two backup strategies that can be implemented, traditional backup to
tape or continuous backup to disk.
Traditional Backups – Traditional or scheduled backups to tape have proven to be an effective and inexpensive means for data protection and recovery. The key benefits of traditional
tape backups include:
• Inexpensive medium to store data
•
•
Portable format that can easily be moved offsite
Familiar to administrators, who know and understand tape backups
For the purposes of this white paper, we use a traditional backup strategy to a Dell PowerVault
TL-Series tape library and it is assumed that the backup window is 16 hours and the amount of
data to be backed up is approximately 70 GB per system.
Implementing the Strategy within Backup Exec
A Dell PowerVault TL2000 can accommodate up to 2 tape drives (2U) and a TL4000 can accommodate up to 4 tape drives (4U) and backup jobs can be created to utilize each drive in the
tape library. For this environment, we will be running a full backup on every Sunday night of
the week and incremental backups throughout the week to ensure adequate data protection.
Incremental backups store only the changes made from the last full or incremental backup job.
Incremental backups are used during the week to minimize the backup of duplicate or unchanged data. Since you must restore the last full backup and all following incremental backups to restore lost data, it is recommended that full backups are performed once a week. Another option is to use differential backups, which store the changes made from the last full
backup job, during the week instead of incremental backups. This would further reduce the
restore time, but could also result in more duplication of unchanged data and longer backup
windows during the week.
The steps for creating the full backup job include:
• Select Backup -> New Backup Job from the Backup Exec User Interface. The backup
job selection list will appear.
• Select the resources from the first 5 systems that need to be protected. In this example,
the C: drive is being selected for each system.
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iSCSI for TL-Series Tape Libraries
Figure 20 : Backup Job Selections Screen
Next, select the destination for the backup jobs. In this environment, the Dell TL2000 is being
targeted. Select the Dell TL2000 under the Device and Media setting:
Figure 21 : Device and Media Screen
Next, select the general tab and select ‘Full Using Archive Bit (Archive Bit Rest)’ as the backup
method for files.
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iSCSI for TL-Series Tape Libraries
Figure 22 : Backup Jobs General Settings Screen
Finally, create the schedule for the backup job. Select the schedule tab from the backup wizard. Select the ‘Run according to schedule’ option and select the backup to occur every Sunday night at 8 pm using the calendar view. Now click ‘Submit’ and the job will be ready for
execution. The job will run on the next Sunday night at 8 pm.
Figure 23 : Backup Jobs Schedule Screen
The job can be monitored using the ‘Job Monitor’ tab from the Backup Exec main interface.
The incremental backups can be setup in a similar manner to the full backup that was just
created. The backup wizard is run to select the same data for backup. The differences between the full backup job and the incremental backup job will be:
•
•
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Selecting ‘Incremental using Archive Bit (reset archive bit)’ as the backup method for files
Creating a schedule to run every night of the week at 8 pm excluding Sundays
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iSCSI for TL-Series Tape Libraries
Monitoring Jobs
Backup Exec’s Job Monitor enables you to monitor and perform tasks on the active, scheduled, or completed jobs that have been submitted for processing.
The Job Monitor provides the following tabs:
• Job List - Displays the active jobs and scheduled jobs in the Current Jobs pane. The Job
History pane displays the jobs that are successful, completed with exceptions, failed, and
canceled.
• Calendar - Displays the scheduled, active, and completed jobs in a daily, weekly, or
monthly view.
• System Summary - Displays the details of media server, job, alert, device, and media
activity.
The Job Monitor tab can be used to determine if the current backup strategy is meeting the
defined backup window. That length of each backup job can be viewed in the Elapsed Time
column. If the Elapsed Time is exceeding the backup window, changes can be made to the
backup strategy to help reduce the backup window. Changes to the backup strategy can include:
• Switching from traditional backups to continuous backup
•
•
Incorporating disk based backup folders for traditional backups instead of targeting tape
directly.
Implementing a disk to disk to tape strategy to support offsite storage of backups
Figure 24 : Job Monitor Screen
SECTION 8
SUMMARY
To supplement the growth in iSCSI SANs, Dell has introduced an iSCSI-to-SAS bridge card
option for the TL-series of tape libraries (TL2000 & TL4000) connected to 1Gb Ethernet networks. This offering allows a customer to directly attach a tape backup target to their iSCSI
SAN with little to no degradation in transfer speed, 90 MB/s in most cases. This is the latest
offering in Dell’s continuing pursuit of cost-effective and simplified IT solutions for SMBs.
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