Installing and Configuring MC/ServiceGuard NFS
Configuring an MC/ServiceGuard NFS Package
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 |
| 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 |
Chapter 2 | 43 |
