Sun Cluster Fault Probes

PNM monitors the health of the public network and will switch to backup connections when necessary. However, in the event of the total loss of public network access, PNM will not provide data service or logical host failover. In such a case, PNM will report the loss but it is up to an external fault probe to handle switching between backup nodes.

If you are using VxVM as your volume manager, the Sun Cluster framework is responsible for monitoring each Network Adapter Failover (NAFO) backup group defined per logical host, and initiating a switchover to a backup node when either of the following conditions are met:

• There is total loss of the public network (all NAFO backup groups are unavailable) and the backup node has at least one NAFO group available.

• There is partial loss of the public network--at least one NAFO backup group is still active when more than one (multiple subnets) are defined for a logical host--and the backup node has a greater number of valid, active NAFO backup groups.

If neither of these conditions are met, Sun Cluster will not attempt a switchover.

If your volume manager is Solstice DiskSuite, loss of public network causes the disconnected node to abort and causes the logical hosts mastered by that node to migrate to the backup node.

The Sun Cluster framework monitors the public networks only while the configuration includes a logical host and while a data service is in the "on" state and registered on that logical host. Only those NAFO backup groups that are in use by a logical host are monitored.