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

Chapter 7, SFCFS Administration
CFS Administration
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fsclustadm
The fsclustadm command reports various attributes of a cluster file system. Using
fsclustadm you can show and set the primary node in a cluster, translate node IDs to
host names and vice versa, list all nodes that currently have a cluster mount of the
specified file system mount point, and determine whether a mount is a local or cluster
mount. The fsclustadm command operates from any node in a cluster on which the file
system is mounted, and can control the location of the primary for a specified mount
point. See the fsclustadm(1M) manual page for information on usage.
fsadm
The fsadm command must be run from the primary node; it fails if invoked on
secondaries. See the fsadm(1M) manual page for information on allowable mount
options.
Running Commands Safely in a Cluster Environment
Any UNIX command that can write to a raw device must be used carefully in a shared
environment to prevent data from being corrupted. For shared VxVM volumes, CFS
provides protection by reserving the volumes in a cluster to prevent VxFS commands,
such as fsck and mkfs, from inadvertently damaging a mounted file system from
another node in a cluster. However, commands such as dd execute without any
reservation, and can damage a file system mounted from another node. Before running
this kind of command on a file system, be sure the file system is not mounted on a cluster.
You can run the mount command to see if a file system is a shared or local mount.
Time Synchronization for Cluster File Systems
CFS requires that the system clocks on all nodes are synchronized using some external
component such as the Network Time Protocol (NTP) daemon. If the nodes are not in
sync, timestamps for creation (ctime) and modification (mtime) may not be consistent
with the sequence in which operations actually happened.