Serviceguard NFS Toolkit A.11.11.06, A.11.23.05 and A.11.31.08 Administrator's Guide (October 2011)

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/nfs4/v4_state 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 v4_state 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. . This directory must be located in the
same shared volume as NFS_FLM_HOLDING_DIR.
An example for this parameter is as follows:
NFSv4_FLM_HOLDING_DIR="/pkg1a/v4_state"
• 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 this request generates
the /var/statmon/sm file) to the HA/NFS server and having the package migrate within
this same five seconds window are extremely unlikely.
If you repeatedly experience a problem with this corner-case scenario, reduce the copy time
interval by setting the PROPAGATE_INTERVAL parameter to a lower value.
Editing the NFS Monitor Script (nfs.mon)
The NFS monitor script, nfs.mon, contains NFS-specific monitor variables and functions. The
nfs.mon script is an optional component of HA/NFS. The hanfs.sh file specifies whether the
NFS monitor script is used. The following steps describe how to configure the NFS monitor script:
1. To monitor the File Lock Migration script (nfs.flm), set the NFS_FILE_LOCK_MIGRATION
variable to 1, and set the NFS_FLM_SCRIPT name to match the hanfs.sh script value for
this variable:
NFS_FILE_LOCK_MIGRATION=1 NFS_FLM_SCRIPT="${0%/*}nfs1.flm"
Configuring a Serviceguard NFS Legacy Package 29