Veritas Storage Foundation™ 5.0.1 for Oracle RAC Installation, Configuration, and Administrator's Guide Extracts for the HP Serviceguard Storage Management Suite on HP-UX 11i v3

Adding nodes to the cluster can also result in too small a log size. In this situation, VxVM marks
the log invalid and performs full volume recovery instead of using DRL.
About CFS
Review CFS File System benefits, CFS configuration differences from VxFS and CFS recovery
operations.
CFS File System Benefits
Many features available in VxFS do not come into play in an SGeRAC environment because
ODM handles such features. CFS adds such features as high availability, consistency and
scalability, and centralized management to VxFS. Using CFS in an SGeRAC environment provides
the following benefits:
• Increased manageability, including easy creation and expansion of files
Without a file system, you must provide Oracle with fixed-size partitions. With CFS, you
can grow file systems dynamically to meet future requirements.
• Less prone to user error
Raw partitions are not visible and administrators cannot compromise them by mistakenly
putting file systems over the partitions. Nothing exists in Oracle to prevent you from making
such a mistake.
• Data center consistency
If you have raw partitions, you are limited to a RAC-specific backup strategy. CFS enables
you to implement your backup strategy across the data center.
CFS Configuration Differences
The first node to mount a CFS file system as shared becomes the primary node for that file system.
All other nodes are “secondaries” for that file system.
Use the fsclustadm command from any node to view which node is primary and set the CFS
primary node for a specific file system.
Mount the cluster file system individually from each node. The -o cluster option of the mount
command mounts the file system in shared mode, which means you can mount the file system
simultaneously on mount points on multiple nodes.
When using the fsadm utility for online administration functions on VxFS file systems, including
file system resizing, defragmentation, directory reorganization, and querying or changing the
largefiles flag, run fsadm from the primary node. This command fails from secondaries.
CFS Recovery
The vxfsckd daemon is responsible for ensuring file system consistency when a node crashes
that was a primary node for a shared file system. If the local node is a secondary node for a given
file system and a reconfiguration occurs in which this node becomes the primary node, the kernel
requests vxfsckd on the new primary node to initiate a replay of the intent log of the underlying
volume. The vxfsckd daemon forks a special call to fsck that ignores the volume reservation
protection normally respected by fsck and other VxFS utilities. The vxfsckd can check several
volumes at once if the node takes on the primary role for multiple file systems.
After a secondary node crash, no action is required to recover file system integrity. As with any
crash on a file system, internal consistency of application data for applications running at the
time of the crash is the responsibility of the applications.
24 Planning SGeRAC Installation and Configuration