Managing Serviceguard NFS for Linux, September 2006

Serviceguard NFS for LINUX Introduction
How the Control and Monitor Scripts Work
Chapter 116
NOTE To configure NFS for maximal availability, you must do the following:
• To have the NFS package start automatically when the cluster starts
up, and to start on an adoptive node after a failure, you need to
specify AUTO_RUN=YES in the package configuration file.
• Also, the default NFS control script does not invoke the NFS
monitoring script, nfs.mon. To invoke this script (see Chapter 3,
“Sample Configurations,”) to trigger a failover if one of the package’s
NFS services goes down while the node and network remain up.
Whenever the monitor script detects an event, it logs information to a file
using the same name as your NFS control script adding a .log
extension. Each NFS package has its own log file. For example, if your
control script is called pkg1.cntl, the package log file is called
pkg1.cntl.log. The NFS monitor log file, which is on the same
directory as the NFS control script, is always called hanfs.sh.log
Remote mount table synchronization
With NFS toolkit, a remote mount table synchronization binary code is
installed in /usr/bin/sync_rmtab. This program is provided for
synchronizing the client current mount table, /var/lib/nfs/rmtab, in
the case of a NFS package failover. This synchronization process ensures
NFS clients access NFS seamlessly in the case of the NFS package
failover. The NFS control script, hanfs.sh, calls the synchronization
program when the remote mount table needs to be synchronized.
On the Client Side
The client should NFS-mount a file system using the package name in
the mount command. The package name is associated with the package’s
relocatable IP address. On client systems, be sure to use a hard mount
and set the proper retry values for the mount. Alternatively, set the
proper timeout for auto-mounter. The timeout should be greater than the
total end-to-end recovery time for the Serviceguard NFS package—that
is, running fsck, mounting file systems, and exporting file systems on
the new node. Setting the timeout to a value greater than the recovery
time allows clients to reconnect to the file system after it returns to the
cluster on the new node.