Using NFS as a filesystem type with HP Serviceguard A.11.20 on HP-UX 11i v3, September 2010

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Supported configurations
• Supported only on HP-UX 11i v3.
• Supported only for modular-style failover packages (see chapter 6 of the latest version of Managing
Serviceguard for information about package types).
• Supported only on Serviceguard A.11.20 or later
Recommendations
• If the storage is directly connected to all the nodes and shared, configure the storage as a local
filesystem rather than using via NFS.
• The same NFS share or files should not be written by multiple nodes or applications at the same
time.
• A given NFS share should be mounted on only one mount point at any time.
• Only the cluster nodes may have access to filesystems they import.
• Do not use AutoFS on the cluster nodes which are configured to run the NFS package.
Serviceguard assumes that an NFS share which is used as part of the Serviceguard package is not
mounted on any nodes before the NFS package starts. If AutoFS mounts the NFS share on the
Serviceguard node, the mount may fail on startup or failover.
• Disable CacheFS for all the filesystems used by the Serviceguard NFS packages on all the cluster
nodes which are configured to run the NFS package.
• The NFS server itself should be highly available.
The specific configuration will depend on the server platform being used.
It is possible to have the package that uses the NFS filesystem as shared storage and the package
that provides the NFS filesystem running in the same cluster.
In such a configuration, the NFS client package must not depend on the NFS server package. If the
NFS server package fails over, the client package need not be failed over. The NFS client package
can continue to run and can reconnect to the NFS server once the NFS server package is up.
• Any NFS filesystems used by the Serviceguard packages should be configured to restrict access to
the nodes in the Serviceguard cluster.
Serviceguard supports exclusive activation for volume groups—for example, LVM volume groups.
When you use NFS client-side locks, which HP recommends, exclusive activation is not available, so
you must make sure you follow these recommendations:
– Only the cluster nodes can have access to the filesystem.
– The filesystem is used by only one Serviceguard failover package.
– If the package fails, you never manually restart it without first ensuring that the filesystem has
been properly unmounted.
Limitations
• An NFS filesystem must be used by only one Serviceguard failover package.
• NFS filesystems used by Serviceguard packages must be mounted with the “llock” mount option to
enforce local locking semantics on the NFS client.
• Mount NFS-imported filesystems used by Serviceguard packages only as part of starting the
package.
A cluster node must not mount NFS shares that are configured as part of any Serviceguard package
as part of the boot up process; otherwise the package may fail when it starts or fails over.