Consider the following points when you plan Solaris Volume Manager configurations:
Dual-string mediators – A disk string consists of a disk enclosure, its physical disks, cables from the enclosure to the host or hosts, and the interface adapter cards. Each disk set configured with exactly two disk strings and mastered by exactly two or three Oracle Solaris hosts is called a dual-string disk set. This type of disk set must have Solaris Volume Manager dual-string mediators configured. Observe the following rules when you configure dual-string mediators:
You must configure each disk set with two or three hosts that act as mediator hosts.
You must use the hosts that can master a disk set as mediators for that disk set. If you have a campus cluster, you can also configure a third node or a non-clustered host on the cluster network as a third mediator host to improve availability.
Mediators cannot be configured for disk sets that do not meet the two-string and two-host requirements.
See the mediator (7D) man page for details.