Guidelines for Volume-Manager Software

Consider the following general guidelines when you configure your disks with volume-manager software:

• Mirrored multihost disks – You must mirror all multihost disks across disk expansion units. See Guidelines for Mirroring Multihost Disks for guidelines on mirroring multihost disks. You do not need to use software mirroring if the storage device provides hardware RAID as well as redundant paths to disks.

• Mirrored root – Mirroring the root disk ensures high availability, but such mirroring is not required. See Mirroring Guidelines for guidelines about deciding whether to mirror the root disk.

• Unique naming – You might have local Solstice DiskSuite metadevices, local Solaris Volume Manager volumes, or VxVM volumes that are used as devices on which the /global/.devices/node@nodeid file systems are mounted. If so, the name of each local metadevice or local volume must be unique throughout the cluster.

• Node lists – To ensure high availability of a disk device group, make its node lists of potential masters and its failback policy identical to any associated resource group. Or, if a scalable resource group uses more nodes than its associated disk device group, make the scalable resource group's node list a superset of the disk device group's node list. See the resource group planning information in the Sun Cluster 3.1 Data Service Planning and Administration Guide for information about node lists.

• Multiported disks – You must connect, or port, all disks used to construct a device group within the cluster to all of the nodes that are configured in the node list for that device group. Solstice DiskSuite/Solaris Volume Manager software can automatically check for this connection at the time that disks are added to a diskset. However, configured VxVM disk groups do not have an association to any particular set of nodes.

• Hot spare disks – You can use hot spare disks to increase availability, but hot spare disks are not required.

See your volume-manager documentation for disk layout recommendations and any additional restrictions.