1.5.2 Fault Monitor Layer

The fault monitor layer consists of a fault daemon and the programs used to probe various parts of the data service. If the fault monitor layer detects a service failure, it can attempt to restart the service on the same node, or initiate a failover of the logical host, depending on how the data service is configured.

Under certain circumstances a data service fault monitor will not initiate a failover even though there has been an interruption of a service. These exceptions include:

• File systems under control of a logical host are being checked with fsck(1M).

• The NFS^TM file system is locked by using lockfs(1M).

• The name service (NIS, NIS+, DNS) is not working. The name service exists outside the Sun Cluster configuration so you must ensure its reliability.