Veritas Storage Foundation 5.0.1 Cluster File System Administrator's Guide Extracts for the HP Serviceguard Storage Management Suite on HP-UX 11i v3

IMPORTANT: Once disk group and mount point multi-node packages are created with HP
Serviceguard, it is critical to use the CFS commands, including cfsdgadm, cfsmntadm,
cfsmount, and cfsumount. If the HP-UX mount and umount commands are used, serious
problems such as writing to the local file system, instead of the cluster file system, could occur.
You must not use the HP-UX mount command to provide or remove access to a shared file
system in a CFS environment (for example, mount -ocluster, dbed_chkptmount, or
sfrac_chkptmount). These non-CFS commands could cause conflicts with subsequent CFS
command operations on the file system or the Serviceguard packages. Use of HP-UX mount
commands will not create an appropriate multi-node package, which means cluster packages
will not be aware of file system changes. Instead, use the CFS commands - cfsmount or
cfsumount.
The fsclustadm and fsadm commands are useful for configuring cluster file systems.
• 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.
• fsadm
The fsadm command is designed to perform selected administration tasks on file systems.
It can be invoked from a primary or secondary node. These tasks may differ between file
system types. A special device file contains an unmounted file system. A special file system
could be a directory, if it provides online administration capabilities. A directory must be the
root of a mounted file system.
See the fsadm(1M) manual page.
• Running commands safely in a cluster environment
Any HP-UX 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
with no options 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.
Growing a Cluster File System
There is a CVM master node as well as a CFS primary node. When growing a file system, you
grow the volume from the CVM master node, and then grow the file system from any CFS node.
The CVM master node and the CFS primary node can be two different nodes.
To determine the primary file system in a cluster (CFS primary), enter:
26 Cluster File System Administration