VERITAS Volume Manager 3.1 Administrator's Guide

Initialization and Setup
System Setup Guidelines
Chapter 280
• Follow the mirroring guidelines described in “Mirroring Guidelines”.
RAID-5 Guidelines
NOTE You may need an additional license to use this feature.
Follow these general guidelines when using RAID-5. See “RAID-5” for
more information.
In general, the guidelines for mirroring and striping together also apply
to RAID-5. The following guidelines should also be observed with
RAID-5:
• Only one RAID-5 plex can exist per RAID-5 volume (but there can be
multiple log plexes).
• The RAID-5 plex must be derivedfrom at least two subdisks on two or
more physical disks. If any log plexes exist, they must belong to disks
other than those used for the RAID-5 plex.
• RAID-5 logs can be mirrored and striped.
• If the volume length is not explicitly specified, it is set to the length of
any RAID-5 plex associated with the volume; otherwise, it is set to
zero. If the volume length is set explicitly, it must be a multiple of the
stripe unit size of the associated RAID-5 plex, if any.
• If the log length is not explicitly specified, it is set to the length of the
smallest RAID-5 log plex that is associated, if any. If no RAID-5 log
plexes are associated, it is set to zero.
• Sparse RAID-5 log plexes are not valid.