Managing Serviceguard NFS for Linux, March 2009

NOTE: To use the lock migration feature, all the configurations specified above must be
done. Also, consider the lock migration feature limitations described in section“Limitations
of the NFS File Lock Migration Feature” (page 8).
9. NFS_FLM_HOLDING_DIR:
NFS File Lock Migration (FLM) directory is a unique directory created in one of the shared
volumes associated with this package. This directory holds copies of the /var/lib/nfs/
sm files on SLES and /var/lib/nfs/statd/sm files on Red Hat for this package.
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). Dedicate the
FLM directory for holding SM entries only.
NOTE: Do not add any files as this directory is maintained by the toolkit. 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 This directory should be present in one of the file
systems specified in the package configuration file.
10. PROPAGATE_INTERVAL:
Number of seconds between attempts of the script to copy files from the /var/lib/nfs/
sm directory on SLES and /var/lib/nfs/statd/sm on Red Hat into the holding directory,
specified by NFS_FLM_HOLDING_DIR. The default value of this parameter is five seconds.
For example: PROPAGATE_INTERVAL 5
NOTE: The NFS client may not receive a crash notification if it sends an initial lock request
to the NFS server and during the interim, the NFS package fails over to an adoptive node
before the FLM script copies the /var/lib/nfs/statd/sm entry on Red Hat and /var/
lib/nfs/sm entry on SLES for this client to the package holding directory. Therefore, the
client may not reclaim the lock once the NFS package fails over to the adoptive node. The
probability of this occurring within the default time interval between copies is extremely
low as the SM file copy interval is very short (by default, five seconds). You can reduce the
probability further by configuring the time interval to a value lower than the default.
11. NFS_FLM_MONITOR:
To monitor the file lock migration script (nfs.flm) by the NFS monitor script (nfs.mon), set
the NFS_FLM_MONITOR variable to “YES”. The default value is NO. Setting this parameter
to “YES” ensures that the lock status files are being copied into holding directory.
12. NFS_FLM_RESTART:
Number of times the monitoring script should attempt to restart the file lock migration script
(nfs.flm) if it fails. The default value is 4.
NOTE: To use the lock migration feature, do all the configurations specified above and
consider all the limitations mentioned in the section “Limitations of the NFS File Lock
Migration Feature” (page 8).
13. Set Service parameters to run NFS monitor service.
a. Set service_name parameter. Each package must have an unique service_name.
For example: service_name nfs_service
b. Set service_fail_fast_enabled to YES if lock migration is enabled. For example:
service_fail_fast_enabled YES
Configuring a Modular Serviceguard NFS Package 29