Novell LINUX ENTERPRISE 11 - HIGH AVAILABILITY, Manual, Page: 118 / 298

• 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 the
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 scala-
bility 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 per-
formance.
12.2 Management Utilities and
Commands
OCFS2 utilities are described in the following table. For information about syntax for
these commands, see their man pages.
108 High Availability Guide