Overview of Serviceguard NFS
Overview of the NFS File Lock Migration Feature
Overview of the NFS File Lock Migration
Feature
Serviceguard NFS introduced the “File Look Migration” feature beginning with versions A.11.11.03 and A.11.23.02. The detailed information on this feature is as follows:
•Each HA/NFS package designates a unique holding directory located in one of the filesystems associated with the package. In other words, an empty directory is created in one of the filesystems that moves between servers as part of the package. This holding directory is a configurable parameter and must be dedicated to hold the Status Monitor (SM) entries only.
•A new script, nfs.flm, periodically (default value is five seconds; you can change this value by modifying the PROPAGATE_INTERVAL parameter in the nfs.flm script) copies SM entries from the /var/statmon/sm directory into the package holding directory. To edit the nfs.flm script, see “Editing the File Lock Migration Script (nfs.flm)” on page 42.
•Upon package failover, the holding directory transitions from the primary node to the adoptive node, because it resides in one of the filesystems configured as part of the HA/NFS package.
Once the holding directory is on the adoptive node, the SM entries residing in the holding directory are copied to the /var/statmon/sm directory on the adoptive node. This populates the new server’s SM directory with the entries from the primary server.
•After failover, the HA/NFS package IP address is configured on the adoptive node, and rpc.statd and rpc.lockd are killed and restarted. This killing and restarting of the daemons triggers a crash recovery notification event, whereby rpc.statd sends crash notification messages to all the clients listed in the
/var/statmon/sm directory.
These crash recovery notification messages contain the relocatable hostname of the HA/NFS package that was previously running on the primary node and is currently running on the adoptive node.
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