Serviceguard NFS Toolkit A.11.11.04 and A.11.23.03 Administrator's Guide

Installing and Configuring Serviceguard NFS
Configuring a Serviceguard NFS Package
Chapter 242
Editing the File Lock Migration Script (nfs.flm)
The File Lock Migration script, nfs.flm, handles the majority of the
work involved in maintaining file lock integrity that follows an HA/NFS
failover. The nfs.flm script includes the following configurable
parameters:
• NFS_FLM_HOLDING_DIR - Name of a unique directory created in one of
the shared volumes associated with this package. This directory
holds copies of the /var/statmon/sm files for this package. You must
create this directory in one of the shared volumes associated with
this package so that it can migrate with the package (from the
primary server to the adoptive server).
You must dedicate this directory for holding SM entries only. In
addition, you must keep it empty. This directory should not have
other files or subdirectories when starting the cluster. All files in this
directory are deleted after a failover.
An example for this parameter is as follows:
NFS_FLM_HOLDING_DIR="/pkg1a/sm"
• PROPAGATE_INTERVAL - Number of seconds between the attempts of
the script to copy files from the /var/statmon/sm directory into the
holding directory, specified by NFS_FLM_HOLDING_DIR. The default
value of this parameter is five seconds.
An example for this parameter is as follows:
PROPAGATE_INTERVAL=5
NOTE If you enable the File Lock Migration feature, an NFS client (or
group of clients) may hit a corner case of requesting a file lock on the
HA/NFS server and not receiving a crash recovery notification
message when the HA/NFS package migrates to an adoptive node.
This occurs only when the NFS client sends its initial lock request to
the HA/NFS server and then the HA/NFS package moves to an
adoptive node before the FLM script copies the /var/statmon/sm
entry for this client to the package holding directory.
The probability of hitting this corner-case problem is not very high,
because the SM file copy interval is very short (by default, five
seconds). The chances of an NFS client (or group of NFS clients)
sending its initial lock request (it must be the initial request, since
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