Switched logical units
A switched logical unit is an independent disk pool. When switched logical units are combined with IBM® i clusters technology, you can create a simple and cost effective high availability solution for planned and some unplanned outages.
The device cluster resource group (CRG) controls the independent disk pool, which can be switched automatically in the case of an unplanned outage, or it can be switched manually by a switchover.
A group of systems in a cluster can take advantage of the switchover capability to move access to the switched logical unit pool from system to system. A switchable logical unit must be in an IBM System Storage® connected through a storage area network. When the independent disk pool is switched the logical units within the IBM System Storage unit are reassigned from one system to another system. See PowerHA supported storage server, for the storage technologies that support switchable logical units.