3.7.0 HP StorageWorks HP Scalable NAS File Serving Software administration guide - HP Scalable NAS 3.7 for Linux (AG513-96002, October 2009)

selects a network interface for failover. If the events are considered, the network
interface for the affected server becomes less desirable.
• For service monitors, you can assign a priority to each monitor (the Service Priority
setting). If ClusterPulse cannot locate an interface where all services are “up” on
the underlying server, it selects an interface where the highest priority service is
“up” on the underlying server.
Specify failback behavior of the virtual host
When you configure a virtual host, you can specify the failback action that the virtual
host will take following a failover to a backup server. There are two options:
AUTOFAILBACK and NOFAILBACK.
AUTOFAILBACK is the default for virtual hosts. (Some HP products may provide
entities that use NOFAILBACK as the default.)
AUTOFAILBACK
AUTOFAILBACK is intended to return the virtual host to its original configuration, or
as close to it as possible. After the virtual host fails over to a backup server,
ClusterPulse watches the health of the servers higher in the list for that virtual host.
When the health of one of these servers is equal to or greater than the backup server
where the virtual host currently resides, the virtual host automatically attempts to fail
over to that server.
NOFAILBACK
NOFAILBACK is intended to minimize failovers. The virtual host remains active on
the backup server until a healthier server (it’s health is greater than the backup server)
becomes available, at which point the virtual host will fail over to that server.
For example, consider a two-node cluster that is configured with its primary on node
1 and backup on node 2, and that uses the NOFAILBACK option. Three service
monitors are configured on the virtual host. When a service monitor probe fails on
node 1, the virtual host will fail over to node 2. Following are some possible failback
scenarios:
• When the monitored service is restored on node 1, the virtual host will remain
on node 2. Node 1 and node 2 are equally healthy; they both have three up
service monitors. The NOFAILBACK policy will not move the virtual host until a
healthier server is available.
• After the virtual host fails over to node 2, a service monitor probe fails on that
node. Now both nodes have a down service monitor. Failback does not occur
Configure virtual hosts312