Planning Volume 2, Control Workstation and Software Environment

Planning for IBM Virtual Shared Disk and Recoverable Virtual Shared Disk Optional Components of PSSP

Plan how you are going to use the Virtual Shared Disk and Recoverable Virtual Shared Disk software before you install the hardware. Consider the following:

• The Virtual Shared Disk subsystem lets you assign volume groups located on any physical disks in any node within a partition. Volume groups assigned to be used by the Virtual Shared Disk subsystem ought to be used only to define virtual shared disks.
• Each virtual shared disk cluster must be in the same system partition. You can have separate virtual shared disk clusters in separate system partitions, but they cannot communicate directly with each other. See Chapter 7, Planning SP system partitions for system partition planning information.
• In order to provide recovery, the Recoverable Virtual Shared Disk software requires twin-tailed disk storage which must be installed before you define or use the virtual shared disks. It also requires a minimum of two SP nodes.

See the book PSSP: Managing Shared Disks for additional explanation of these and other dependencies and restrictions.