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The import locking scheme works well in an environment where disk groups are not normally shifted from one system to another. However, consider a setup where two hosts, Node A and Node B, can access the drives of a disk group. The disk group is first imported by Node A, but the administrator wants to access the disk group from Node B if Node A crashes. Such a failover scenario can be used to provide manual high availability to data, where the failure of one node does not prevent access to data. Failover can be combined with a "high availability" monitor to provide automatic high availability to data: when Node B detects that Node A has crashed or shut down, Node B imports (fails over) the disk group to provide access to the volumes.
Veritas Volume Manager can support failover, but it relies on the administrator or on an external high-availability monitor to ensure that the first system is shut down or unavailable before the disk group is imported to another system.
See "Moving disk groups between systems" on page 194.