VERITAS Storage Foundation 4.1 Cluster File System HP Serviceguard Storage Management Suite Extracts, December 2005

Chapter 7, SFCFS Administration

CFS Overview

CFS Primary and CFS Secondary

The primary file system handles the metadata intent logging for the cluster file system.

The first node of a cluster file system to mount is called the primary node. Other nodes are

called secondary nodes. If a primary node fails, an internal election process determines

which of the secondaries becomes the primary file system.

Use the following command to determine primaryship:

# fsclustadm –v showprimary mount_point

Use the following command to give primaryship to a node:

# fsclustadm –v setprimary mount_point

A cluster file system node can be mounted using the mount seconly option to prevent it

from ever assuming the primaryship of the cluster. If a primary node fails and all the

remaining nodes in the cluster file system are mounted as secondary-only, the cluster is

disabled. The mount seconly option overrides any setting by the fsclustadm

command. See the mount_vxfs(1M) man page for more information on the seconly

option.

Asymmetric Mounts

Asymmetric mounts allow shared file systems to be mounted with different read/write

capabilities. So one node in the cluster can mount read-write, while other nodes mount

read-only.

You can specify the cluster read-write (crw) option when you first mount the file system,

or the options can be altered when doing a remount (mount –o remount). The first

column in the following table shows the mode in which the primary is mounted. The

check marks indicate the mode secondary mounts can use.

Only mounting the primary with –o cluster,ro prevents the secondaries from

mounting in a different mode, that is, read-write mode. Note that rw implies read-write

capability throughout the cluster.

See the mount_vxfs(1M) man page for information on the cluster read-write (crw)

mount option.

Secondary

Primary

ro rw ro, crw

✔

✔✔

ro, crw

✔✔