Serviceguard NFS Toolkit A.11.31.02, A.11.11.06, and A.11.23.05 Administrator's Guide

1 Overview of Serviceguard NFS
Serviceguard NFS is a tool kit that enables you to use Serviceguard to set up highly
available NFS servers.
You must set up a Serviceguard cluster before you can set up Highly Available NFS.
For instructions on setting up a Serviceguard cluster, see the Managing Serviceguard
manual.
Serviceguard NFS is a separately purchased set of configuration files and control script,
which you customize for your specific needs. These files, once installed, are located in
/opt/cmcluster/nfs.
Serviceguard allows you to create high availability clusters of HP 9000 Series 800
computers on HP-UX 11i v1 and HP-UX 11i v2 systems. On HP-UX 11i v3 systems,
clusters may comprise of both HP Integrity servers and HP 9000 Series 800 computers.
A high availability computer system allows applications to continue in spite of a
hardware or software failure. Serviceguard systems protect users from software failures
as well as from failure of a system processing unit (SPU) or local area network (LAN)
component. In the event that one component fails, the redundant component takes
over, and Serviceguard coordinates the transfer between components.
An NFS server is a host that “exports” its local directories (makes them available for
client hosts to mount using NFS). On the NFS client, these mounted directories look
to users like part of the client’s local file system.
With Serviceguard NFS, the NFS server package containing the exported file systems
can move to a different node in the cluster in the event of failure. After Serviceguard
starts the NFS package on the adoptive node, the NFS file systems are re-exported from
the adoptive node with minimum disruption of service to users. The client side hangs
until the NFS server package comes up on the adoptive node. When the service returns,
the user can continue access to the file. You do not need to restart the client.
Limitations of Serviceguard NFS
The following limitations apply to Serviceguard NFS:
• Applications lose their file locks when an NFS server package moves to a new
node. Therefore, any application that uses file locking must reclaim its locks after
an NFS server package fails over.
An application that loses its file lock due to an NFS package failover does not
receive any notification. If the server is also an NFS client, it loses the NFS file locks
obtained by client-side processes.
Limitations of Serviceguard NFS 9