Oracle ACFS 12c Release 2.
Introduction and Technical Overview
ORACLE WHITE PAPER
|
NOVEMBER 2017
0 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Table of Contents
Introduction
1
Oracle ACFS High Level Architecture
2
Oracle ACFS Advanced Functionality
3
Oracle ACFS Security
3
Oracle ACFS Encryption
3
Oracle ACFS Compression
3
Oracle ACFS Auditing
3
Oracle ACFS Snapshots
4
Oracle ACFS Snapshot-based Replication
4
Oracle ACFS Tagging
5
Oracle ACFS Accelerator Volume
5
Oracle ACFS Defragging
6
Oracle ACFS Automatic Resize
6
Oracle ACFS NAS Maximum Availability eXtensions (MAX)
6
Oracle ACFS Sparse File Support
6
Oracle ACFS Performance
7
Oracle Platform Support
9
Oracle ACFS on Exadata Database Machine
9
Oracle ACFS Use Cases
10
Conclusion
11
1 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Introduction
Oracle ASM Cluster File System (ACFS) is an industry standard, POSIX, X/OPEN and Windows
compliant cluster file system. It supports multiple operating systems and server platforms including
traditional server environments, the Oracle Exadata Database Machine and Oracle Database
Appliance. It includes advanced features such as file system snapshots, replication, tagging, security,
encryption, auditing, and highly available NFS and SMB services. Starting with Oracle Database 12c
Release 2 features such as snapshot-based replication, compression, automatic resize, NAS
Maximum Availability extensions, support for sparse files, metadata acceleration, among others, were
introduced.
Oracle ACFS is integrated with Oracle Automatic Storage Management, extending its functionalities to
support general-purpose files. Starting with Oracle Database 12c Release 1, ACFS also supports
Oracle Database files. Oracle ACFS is designed to have direct access to Oracle ASM disk group
storage for the shortest I/O path to deliver optimal performance. Through it’s underlying extent-based
architecture, Oracle ACFS provides fast file access, high throughput and fast response time.
Oracle ACFS also includes Oracle ADVM, a dynamic cluster volume manager. Oracle ADVM provides
volume management services and a standard device driver interface for system administrators to
manage volumes across different nodes of a cluster with the same functionality on multiple platforms.
Oracle ADVM volumes inherits key ASM features that includes striping, mirroring, rebalancing,
intelligent data placement, preferred read, fast resync, even read, Flex ASM and many more.
Oracle ACFS leverages Oracle Clusterware for cluster membership state transitions and resourcebased high availability. Oracle ACFS, ADVM, Oracle ASM and Oracle Clusterware are all bundled into
the Oracle Grid Infrastructure (GI) allowing for integrated optimized management of databases
resources, volumes and file systems.
Oracle ACFS provides a scalable, high performance and highly available solution that simplifies
system and storage management through one management interface, one set of installation and
configuration tools, one cluster framework and one vendor for support.
1 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Oracle ACFS High Level Architecture
Oracle ACFS is a complete storage solution that offers performance, simple manageability and high availability.
Oracle ACFS is integrated with Oracle ASM and Oracle Clusterware as shown in diagram 1 below. It communicates
with Oracle ASM to store metadata locally which allows for direct access to ASM disk group storage for maximum
performance. It also communicates with Oracle Clusterware to facilitate resource management for ACFS.
Diagram 1.
Upon creation of an Oracle ADVM volume a dynamic volume file is created for interface purposes of Oracle ACFS
with Oracle ASM storage. During the creation of a file system, Oracle ACFS will refer to this file, upon configuration
and mounting, the file system will inherit all Oracle ASM features associated with the related Oracle ADVM volume.
Communication between Oracle ACFS and the Oracle ASM instance will now be performed through the Oracle
ACFS driver. However, all I/O will go directly from Oracle ACFS to the Oracle ASM storage.
Oracle ACFS Clusterware support allows for Clusterware resources to take over operations such as cluster
membership state transitions, driver loading, mount and unmount of file systems, enabling and disabling of volumes
and providing High Availability for both Oracle ACFS and Oracle ADVM resources.
Oracle ACFS supports up to 64 mounted file systems for 32-bit systems, and up to 256 mounted file systems for 64bit systems. File support in Oracle ACFS is for 1 trillion files in a file system, and there is no directory limit.
Oracle ASM disk group compatibility attributes set the storage limits for both Oracle ACFS and Oracle ASM, for
1
further information please refer to the Oracle ASM Administrator’s guide .
1
HTTPS://DOCS.ORACLE.COM/DATABASE/122/OSTMG/OSTMG.PDF
2 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Oracle ACFS Advanced Functionality
Oracle ACFS Security
Oracle ACFS, similar to Oracle Database Vault, provides realm-based security. A realm, under Oracle ACFS, is a
group of files or directories; only defined user or set of users can access this group. Each realm has a set of rules to
enforce fine grain access control beyond what is provided initially by the operating system. Oracle ACFS Security
data is logged for auditing and diagnostic purposes.
Oracle ACFS Security, provides protection from unauthorized access to the following elements:
» Oracle ACFS Security Objects
» Security realms, rules and rules sets
» Oracle ACFS Security Directory
» Log files and security metadata backup files.
» Oracle ACFS realm-secured user files and directories
Oracle ACFS Encryption
Oracle ACFS file system data can be kept in an encrypted format through ACFS Encryption, allowing the user to
encrypt individual files, directories or entire file systems. By offering encryption, Oracle ACFS users are protected
against any unauthorized use, even in case of theft or data loss through disk failures. Oracle ACFS allows for coexistence of encrypted and non-encrypted files in the same Oracle ACFS file system. Applications will work
unchanged and unaffected by the presence of file encryption.
Oracle ACFS encryption offers two different encryption keys, a file encryption key for files and a volume encryption
key for file systems and encrypting file encryption keys. For key storing purposes, Oracle ACFS supports Oracle
Cluster Registry (OCR) and starting with Oracle Database 12c Release 1 (12.1.0.2), Oracle Key Vault.
Oracle ACFS Compression
Oracle ACFS 12c Release 2 introduces Compression to its standard set of features. Oracle ACFS Compression is
derived from Oracle’s Database Advanced Compression solution. This solution comprises different sets of files such
as RMAN files, data pump files, general purpose files and archive logs, this excludes redo logs, control files and
flashback logs. Oracle ACFS Compression allows the user to reduce its storage footprint. Once Oracle ACFS
compression is enabled on a file system, only files created afterwards are compressed, also, when disabling Oracle
ACFS compression, compressed files are not automatically uncompressed.
Oracle ACFS Auditing
Oracle ACFS security and encryption can be audited via Oracle ACFS Auditing. All sources of events, in the case of
security and encryption, are called audit sources, while all audit records are written in logs called audit trails. Audit
trails are handled separately for every Oracle ACFS file system; on a cluster environment this include separation by
individual nodes.
3 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Oracle ACFS Auditing can be enabled at the realm level, this allows for auditing of authorizations and security
violations. Oracle ACFS Auditing provides the entire underlying framework for the import of data into the Database
Firewall and the Oracle Audit Vault by an audit vault collector. Oracle ACFS Auditing enables for separation of duties
of the management and review of the audit to be enforced.
Oracle ACFS Snapshots
Oracle ACFS snapshotting functionality provides the ability to generate point in time copies of Oracle ACFS file
systems. Oracle ACFS snapshots can either be read-only or read-write. Oracle ACFS snapshotting uses spaceefficient copy-on-write functionality. In order to maintain a point-in-time view consistency of the file system, Oracle
ACFS file extent values are preserved before they are modified in any way or even deleted.
Oracle ACFS Snapshots will be stored within the file system. IF additional storage for files and snapshots is
needed, Oracle ACFS allows for dynamic resizing of a file system. Upon creation, Oracle ACFS snapshots are ready
and available to be used. Support for up to 1023 Oracle ACFS snapshots is available, snapshot of snapshots are
supported; with full inheritance at any given point in the hierarchy. As long as the the Oracle ACFS file system is
mounted, snapshots will always be available.
Starting with Oracle ACFS 12c Release 2, further acfsutil operating system commands are introduced. The acfsutil
snap duplicate commands are created to enhance replication. The acfsutil snap duplicate commands allows for
create and apply operations.
The acfsutil snap duplicate create command, creates a duplicate snapshot of an already existing snapshot. The
acfsutil snap duplicate apply command “applies” a duplicated snapshot to an existing file system or snapshot. This
operation is an incremental apply, which means if it is the first time, the target file system or snapshot must be
empty, then, after the first apply, all subsequent applies will only include deltas of the snapshot. Oracle ACFS
snaputil commands allow now for snapshot remastering, renaming and quota setting.
Oracle ACFS Snapshot-based Replication
Diagram 2.
4 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Oracle ACFS 12c Release 2 provides replication on a snapshot-based technology to provide maximum efficiency
and flexibility in asynchronous replication. Oracle ACFS Snapshot-based Replication enables replication of an
Oracle ACFS file system across the network from a primary to a standby site. Complemented with Oracle Data
Guard, Oracle ACFS Snapshot-based Replication provides the customer with an end-to-end DR solution for all files.
Oracle ACFS Snapshot-based replication, works by transferring the differences between consecutive snapshots
from the primary file system to the standby file system using the simple ssh protocol. Once an initial snapshot is
replicated from the active to the standby file system, the changes of the successive snapshots will continue to be
replicated. Oracle ACFS Snapshot-based replication carries a timestamp that can be queried for the purpose of
synchronizing database transactions with file system data. Replication of Oracle Database files stored on Oracle
ACFS file system is currently not supported with Oracle ACFS replication.
Oracle ACFS Replication on primary sites running AIX, Linux or Solaris works with standby sites running on any of
the mentioned operating systems, but a primary site running on Windows is able to only replicate to a standby site
also running on Windows. Oracle ACFS Replication allows for auditing, realm-based security and encryption to be
enabled, thus securing the replicated standby file system with any of the policies in place in the primary file system.
Oracle ACFS Tagging
Oracle ACFS Tagging allows a user to associate one or more files as a group by assigning a unique ‘tag name’
attribute. Group operations can be performed based on tagged files that may span across different directories within
an Oracle ACFS file system and within a single node or a cluster. By using Oracle ACFS Tagging, different groups
of tagged files may be replicated as groups of related files, hence not having to replicate entire Oracle ACFS cluster
file systems.
Oracle ACFS Accelerator Volume
Oracle ACFS Accelerator Volume was introduced in Oracle ACFS 12c Release 1 for future use. In Oracle ACFS 12c
Release 2, this feature provides performance improvement for all metadata related operations. Since metadata is
accessed more frequently than data, locating metadata in faster storage, often called an accelerator volume, will
improve performance. ADVM region logging DRL files can also be stored on accelerator storage which optimizes IO
performance for ADVM storage hosting Oracle ACFS file systems. An Oracle ACFS Accelerator Volume should use
faster storage than the one used for the primary volume. The use of an accelerator volume is recommended for files
with many extents; for instance, when there are Oracle ACFS Snapshots in use or for compressed ACFS file
systems, the use of an Accelerator Volume is recommended. For further recommendations on guidelines for
accelerator volumes size, please refer to the Oracle ASM Administrator’s guide 1.
5 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Oracle ACFS Defragging
Oracle ACFS is designed to eliminate the need for file system defragging. However, over time, a file system may
need to be defragmented, specifically when storage is shared among database and snapshots or when the systems
are under constant active workloads. Starting with Oracle ACFS 12c Release 2 a defragging feature is introduced,
working in an automatic fashion in the background.
Oracle ACFS Automatic Resize
Starting on Oracle ACFS 12c Release 2, the acfsutil size command is introduced to provide an option for automatic
file system resizing. With the acfsutil size command, the user specifies how much a file system should grow in case
the available free space reaches certain threshold, also, the user can specify the maximum size a file system can
reach, one the threshold is reached, the system will be automatically resized. This is an important and highly needed
new feature introduced in this release.
Oracle ACFS NAS Maximum Availability eXtensions (MAX)
Oracle ACFS 12c Release 2 introduces a set of High Availability extensions for common NAS protocols, improving
NFS and SMB exported file system availability. Oracle ACFS Maximum Availability eXtensions, while in use,
guarantee that NFS or SMB will run in High Availability mode. This means that as long as there is one cluster node
available, the NFS or SMB exports will be available. Oracle ACFS NAS Maximum Availability eXtensions integrate
with NAS protocols and the Oracle ACFS stack, meaning ease of use without any additional infrastructure.
The High Availability Network File Storage (HANFS) feature enables highly available NFS servers to be configured
using Oracle ACFS clusters, thus providing continuous service of NFS v2/v3/v4 exported paths. The HANFS cluster
configurations may be built from your existing infrastructure or commodity servers and storage. Oracle ACFS now
also supports HANFS NFS v4 with NFS Locks (limited to certain operating systems only – see documentation for
2
details ).
Oracle ACFS NAS Maximum Availability eXtensions offer support for SMB provided to interface with Active Directory
Domains and Microsoft servers. Samba or Microsoft SMB must be in place in order to ensure Oracle ACFS HA3
SMB. For further information please refer to Oracle ACFS NAS Maximum Availability eXtensions whitepaper .
Oracle ACFS Sparse File Support
With Oracle ACFS 12c Release 2, support for sparse files is introduced. Sparse files usually comprise of significant
unused space, support for this files allows Oracle ACFS to leave a gap in the file, rather than allocating space on the
storage for the unused space. This gap will then be “zero filled” in memory when read. This is key since it benefits
NFS client write operations, NFS performance, disk utilization and storage saving for customers.
2
3
http://docs.oracle.com/database/122/OSTMG/understand-acfs-admin.htm#OSTMG95489
http://www.oracle.com/technetwork/database/database-technologies/cloud-storage/acfs/learnmore/acfs-nas-max-wp-3618364.html
6 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Oracle ACFS Performance
Oracle ACFS underlying architecture delivers optimal performance for general-purpose files and Oracle Database
files. Oracle ACFS utilizes a direct I/O path from the database to the ASM disk group devices and hence bypasses
the traditional OS VM page caching mechanism used for file system applications. This model enables ACFS-based
databases to achieve performance metrics comparable to databases configured to use Oracle ASM directly.
Comprehensive internal benchmarks using OLTP and DSS workloads have proven the performance of Oracle
ACFS and Oracle ASM to be similar. Such benchmarks were ran using the following infrastructure:
Diagram 3.
The benchmark configuration for Swingbench is comprised of two database schemas: OE SCHEMA (OLTP), with no
partitioning, no compression, big file tablespace, all indexes, and sizing factor 6, meaning a 19 GB Tablespace, and
the SH SCHEMA (DSS) created with range partitioning, no compression, big file tablespace, all indexes and sizing
factor 41, meaning a 70 GB Tablespace.
The following charts shows performance based on an OLTP workload. As it can be seen, the throughput
performance and transaction response time are almost identical regardless of whether the database use ACFS or
ASM directly. The following comparison was made using ten processes and data is based on the average of 5 thirty
minute test runs on Oracle ASM and Oracle ACFS.
OE workload throughput
14
3000
12
2500
10
8
ASM
ACFS
6
4
2
Transactions per second
Response time (ms)
BT transaction performance
2000
ASM
ACFS
1500
1000
500
0
0
0
500
1000
1500
2000
2500
3000
3500
Number of users
7 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
0
500
1000
1500
2000
Number of users
2500
3000
3500
The operating system and CPU loads show no significant difference between Oracle ACFS and ASM; neither did
the DSS workload as shown in the following:
CPU utilization
IO Performance - Throughput
90
60
80
50
60
50
ASM
ACFS
40
30
20
Throughput (MB/s)
CPU utilization (%)
70
40
ASM-reads
ACFS-reads
ASM-writes
ACFS-writes
30
20
10
10
0
0
500
1000
1500
2000
2500
3000
3500
0
0
Number of users
500
1000
1500
2000
2500
3000
Number of users
PERFORMANCE NUMBERS
ASM
ACFS
% difference
SH Throughput
(TX/min)
3.29
3.26
-1%
IO Throughput
(Reads / sec)
3501
3312
-5%
IO Throughput
(MB Read /
sec)
724
712
-2%
CPU Usage
(%)
16.5
%
16.7 %
+1%
8 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
3500
Oracle Platform Support
Oracle ACFS is supported on multiple operating systems including Linux, Windows, Novell SLES, Solaris and AIX,
for further information regarding kernel and Operating System specifics refer to My Oracle Support note 1369107.1
4
Oracle Engineered Systems where Oracle ACFS is supported include Oracle Database Appliance (ODA) and
Oracle Exadata Database Machine.
Oracle ACFS on ODA
Oracle ACFS is the primary cluster file system to store database files and general purpose data in the Oracle
Database Appliance. Since Oracle ACFS is built on top of Oracle ASM, the Oracle Database Appliance leverages
the best of both products. Oracle Database Appliance adoption of Oracle ACFS provides with a wide array of
functionalities requiring no additional effort or management.
File system management in the Oracle Database Appliance is done automatically by the integrated Appliance
Manager, which means that all storage, including ACFS file systems and their underlying ASM diskgroups require
no administration. By default, three file systems are created in the Oracle Database Appliance. These file systems
are created in the already existing Oracle ASM disk groups, DATA, RECO and REDO. Oracle Database Appliance
leverages Oracle ACFS snapshot capabilities, allowing for provision of test and development environments in the
fastest and efficient way and performance equivalent to Oracle ASM.
Oracle ACFS on Exadata Database Machine
Oracle Exadata Database Machines run Oracle Linux and support Oracle ACFS for all database files and general
purpose files starting with Oracle ACFS 12c Release 1 (12.1.0.2)
Oracle Database files supported in Oracle ACFS on Exadata Database Machines are limited to Oracle Database
10g Rel 2 (10.2.0.4 and 10.2.0.5), 11g (11.2.0.4 and higher) and Oracle Database 12c (12.1.0.1 and higher).
Oracle ACFS, as of now, does not use Oracle Smart Scan (predicate processing) and is not able to push database
operations directly to storage leveraging Oracle Exadata storage. Oracle ACFS snapshot and tagging capabilities
are supported for database files, however replication, security, encryption and audit capabilities are supported only
for general-purpose files. For further information on Oracle ACFS on Exadata Database Machine refer to Oracle
ASM Administrator’s guide.1
4
https://support.oracle.com/epmos/faces/DocContentDisplay?id=1369107.1
9 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Oracle ACFS Use Cases
Oracle ACFS can be used in multiple scenarios that can leverage and benefit from its features and functionality.
Oracle ACFS is ideal for Oracle RAC cluster environments, standalone deployments, Oracle middleware and Oracle
Application environments and other vendor provided environments.
Oracle ACFS use cases range from managing Oracle Database files, general purpose files, shared database
homes, administrative files, log files, trace and audit files, storing and managing business and unstructured data,
delivering NFS/SMB exported file systems, leveraging NFS/SMB to off host backups, complementing Oracle Data
Guard for Disaster Recovery solutions with Oracle ACFS Replication, leveraging snapshotting for quick provisioning
test and development environments, among many other possible implementations.
10 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
Conclusion
Oracle ACFS together with Oracle ASM offers a complete storage solution, a POSIX, X/OPEN and Windows
compliant cluster file system and support of multiple operating systems and server platforms.
It is used by
customers in over 60 countries, used across all industries and leveraged by 40 of the top S&P 500 companies.
Oracle ACFS simplifies management of Oracle Database files and general files and is an optimal solution for test
and development environments.
Advanced functionality, such as replication, compression, tagging, security, auditing, resizing, metadata acceleration
as well as NFS and SMB extensions add to the flexibility and value of Oracle ACFS. Based on those features,
Oracle ACFS provides a complete storage solution delivering performance, manageability and best-in-class
availability.
Performance is ensured via fast file access, utilizing ACFS underlying extent-based architecture. Throughput and
response time go in line with Oracle ASM excellent performance numbers.
Ease of management is provided by complying with industry standards, offering command-line interfaces as well as
graphical tools for administration and its integration with Oracle Clusterware, allowing for automation of key tasks.
Best-in-class availability is ensured by its architecture and design that allows for quick recovery from outages and its
integration with Oracle Clusterware allowing to leverage all cluster membership services.
Last but not least, Oracle ACFS is the best option for costumers looking for a complete and integrated storage
solution designed to reduce total cost of ownership and simplification of system and storage management.
11 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
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Oracle ACFS 12c Release 2 – Introduction and Technical Overview
November 2017
Author: Oracle ACFS Product Management
12 | ORACLE ACFS 12C RELEASE 2. – INTRODUCTION AND TECHNICAL OVERVIEW
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