Sun Cluster Software Installation Guide for Solaris OS

Mirroring Guidelines

This section provides the following guidelines for planning the mirroring of your cluster configuration:

Guidelines for Mirroring Multihost Disks

To mirror all multihost disks in a Sun Cluster configuration enables the configuration to tolerate single-device failures. Sun Cluster software requires that you mirror all multihost disks across expansion units. You do not need to use software mirroring if the storage device provides hardware RAID as well as redundant paths to devices.

Consider the following points when you mirror multihost disks:

For more information about multihost disks, see Multihost Disk Storage in Sun Cluster Overview for Solaris OS and Sun Cluster Concepts Guide for Solaris OS.

Guidelines for Mirroring the Root Disk

Add this planning information to the Local File System Layout Worksheet.

For maximum availability, mirror root (/), /usr, /var, /opt, and swap on the local disks. Under VxVM, you encapsulate the root disk and mirror the generated subdisks. However, Sun Cluster software does not require that you mirror the root disk.

Before you decide whether to mirror the root disk, consider the risks, complexity, cost, and service time for the various alternatives that concern the root disk. No single mirroring strategy works for all configurations. You might want to consider your local Sun service representative's preferred solution when you decide whether to mirror root.

See your volume-manager documentation and Configuring Solaris Volume Manager Software or Installing and Configuring VxVM Software for instructions about how to mirror the root disk.

Consider the following points when you decide whether to mirror the root disk.