/ Chapter 9. Oracle Cluster File System 2 | ||||
|---|---|---|---|---|
 | Part III. Storage and Data Replication | 9.2. Management Utilities and Commands |  | |
/ Chapter 9. Oracle Cluster File System 2 | ||||
|---|---|---|---|---|
| Part III. Storage and Data Replication | 9.2. Management Utilities and Commands | | |
Contents
Oracle Cluster File System 2 (OCFS2) is a general-purpose journaling file system that is fully integrated in the Linux 2.6 kernel and later. OCFS2 allows you to store application binary files, data files, and databases on devices on shared storage. All nodes in a cluster have concurrent read and write access to the file system. A user-space control daemon, managed via a clone resource, provides the integration with the HA stack, in particular OpenAIS and the DLM.
In SUSE Linux Enterprise Server 10 and later, OCFS2 can be used for example for the following storage solutions:
General applications and workloads
XEN image store in a cluster
XEN virtual machines and virtual servers can be stored on OCFS2 volumes that are mounted by cluster servers to provide quick and easy portability of XEN virtual machines between servers.
LAMP (Linux, Apache, MySQL, and PHP | Perl | Python) stacks
In addition, it is fully integrated with OpenAIS.
As a high-performance, symmetric, parallel cluster file system, OCFS2 supports the following functions:
An application’s files are available to all nodes in the cluster. Users simply install it once on an OCFS2 volume in the cluster.
All nodes can concurrently read and write directly to storage via the standard file system interface, enabling easy management of applications that run across a cluster.
File access is coordinated through the Distributed Lock Manager (DLM).
DLM control is good for most cases, but an application’s design might limit scalability if it contends with the DLM to coordinate file access.
Storage backup functionality is available on all back-end storage. An image of the shared application files can be easily created, which can help provide effective disaster recovery.
OCFS2 also provides the following capabilities:
Metadata caching.
Metadata journaling.
Cross-node file data consistency.
Support for multiple-block sizes (each volume can have a different block size) up to 4 KB, for a maximum volume size of 16 TB.
Support for up to 16 cluster nodes.
Asynchronous and direct I/O support for database files for improved database performance.
