VERITAS Volume Manager 3.1 Administrator's Guide

Initialization and Setup
System Setup Guidelines
Chapter 274
System Setup Guidelines
These general guidelines can help you to understand and plan an
efficient storage management system. See the cross-references in each
section for more information about the featured guideline.
Hot-Relocation Guidelines
NOTE You may need an additional license to use this feature.
Follow these general guidelines when using hot-relocation. See
“Hot-Relocation” for more information.
• The hot-relocation feature is enabled by default only if you have the
license for this feature. Although it is possible to disable
hot-relocation, it is advisable to leave it enabled.
• Although hot-relocation does not require you to designate disks as
spares, you can designate at least one disk as a spare within each
disk group. This gives you some control over which disks are used for
relocation. If no spares exist, Volume Manager uses any available free
space within the disk group. When free space is used for relocation
purposes, it is possible to have performance degradation after the
relocation.
• After hot-relocation occurs, you can designate one or more additional
disks as spares to augment the spare space (some of the original
spare space may be occupied by relocated subdisks).
• If a given disk group spans multiple controllers and has more than
one spare disk, you can set up the spare disks on different controllers
(in case one of the controllers fails).
• For a mirrored volume, the disk group must have at least one disk
that does not already contain a mirror of the volume. This disk should
either be a spare disk with some available space or a regular disk
with some free space and the disk is not excluded from hot-relocation
use.
• For a mirrored and striped volume, the disk group must have at least