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

Virtual hosts and failover
When you create a virtual host, you specify a list of network interfaces on which the
virtual host can be located. The interfaces are placed in order: primary, backup #1,
backup #2, and so on. The ClusterPulse process considers the “health” of the servers
providing those interfaces when determining where to place a virtual host. The status
and enablement of the service and device monitors associated with the virtual host
also contribute to a server’s health calculation. When a server is completely “healthy,”
all of the services associated with the virtual host are up and enabled.
When certain events occur on the server where a virtual host is located, the
ClusterPulse process will attempt to fail over the virtual host to another server
configured for that virtual host. For example, if the server goes down, ClusterPulse
will check the health of the other servers and then determine the best location for the
virtual host.
ClusterPulse uses the following virtual-host activeness policy to determine the server
where it will make a virtual host active. In conjunction with this policy, the decisions
that you make when configuring a virtual host and the service or device monitors
associated with it help determine whether virtual host failover occurs, the interface
to which the virtual host will fail over, and what happens when operations are restored
on the original server.
Virtual host activeness policy
The policy described here is accurate for this release but it may change in future
releases. The virtual host activeness policy is as follows:
1. If the virtual host is disabled, it is not made active anywhere.
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