The NFS Server Recovery Kit provides a High Availability NFS service in hierarchical cooperation with the Filesystem Recovery Kit (provided as part of the steeleye-lk package) and the IP Recovery Kit (steeleye-lkIP).

The kit ensures that an IP resource and a file system resource containing the shared mount point are always in-service on the same server in the cluster. Clients who mount the file system using the LifeKeeper-protected IP resource can continue processing files on the volume virtually uninterrupted while the actual export service is switched between servers in the cluster (either manually or in response to a failure). Client recovery times will depend on the interaction between the client and the NFS server. For example, with NFSv3, the protocol timeouts for TCP are longer than that of UDP. In order to determine the best transport layer protocol to use with NFS, consider the recommendations of the OS vendor, the advantages and disadvantages of each transport protocol and your specific environment.

All files on the file system become temporarily unavailable while a switchover or failover is in progress, but they become available again transparently when the resource transfer is complete. For a switchover, this can take between 5 and 30 seconds. For a failover, the recovery time depends on how long it takes to repair the file system. It is strongly recommended that you format the underlying disk volume with a Journaling File System (JFS) which is extremely robust to failure and can be repaired in a few seconds.

Beginning with LifeKeeper v9.6.0, NFS v4 pseudo file system is no longer supported. LifeKeeper cannot protect the fsid=0 export point and its sub directory’s export point. If you are creating a fsid=0 resource using the version prior to LifeKeeper v9.6.0, it is necessary to delete the resource and then upgrade LifeKeeper.

Using the OS default setting, both NFS v3 and 4 are enabled. Specify the version using the mount option on clients.

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