Managing Serviceguard NFS for Linux, March 2009

1 Serviceguard NFS for LINUX Introduction
This manual describes how to install and configure a Serviceguard NFS toolkit on a Linux system.
Serviceguard NFS® is a toolkit that allows you to use Serviceguard to set up highly available
NFS servers.
The information presented in this manual assumes you are familiar with Serviceguard and NFS
operations. Refer to your Serviceguard and/or NFS documentation for additional information.
NOTE: You must set up a Serviceguard cluster before you can set up Highly Available NFS.
For instructions on setting up an Serviceguard Linux cluster, see the Managing HP Serviceguard
for Linux manual.
The NFS server programs must also be installed on your Linux system before you install,
configure, and test your NFS package.
Overview of Serviceguard NFS
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.
Serviceguard allows you to create high availability clusters of HP Linux computers (nodes). 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.
Serviceguard NFS is a separate set of shell scripts, and a binary file. One shell script (NFS control
script) is provided as a template for an NFS server package. Customize this script to meet your
specific needs.
In the event of failure, the NFS server package containing the exported file systems moves to a
different node in the Serviceguard cluster. 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:
• File locks are not maintained when an NFS server package moves to an adoptive node. Any
applications that use file locking must reclaim their locks after an NFS server package fails
over. An application that loses its file lock as a result of an NFS package failover will not be
notified. If the server is also an NFS client, any file locks it holds will be lost.
• A system administrator may need to manually maintain or remove persistent file-lock states
for the failed node. The previous file-lock states may remain available on the failed node.
Overview of Serviceguard NFS 7