VERITAS Volume Manager 3.1 Administrator's Guide

Recovery
Miscellaneous RAID-5 Operations
Chapter 8376
Manipulating RAID-5 Subdisks
As with other subdisks, subdisks of the RAID-5 plex of a RAID-5 volume
are manipulated using the vxsd command. Association is done by using
the assoc keyword in the same manner as for striped plexes. For
example, to add subdisks at the end of each column in the vxprint output
for a RAID-5 volume on “Disk Failures” page 247, use the following
command:
# vxsd assoc r5vol-01 disk10-01:0 disk11-01:1
disk12-01:2
If a subdisk is filling a “hole” in the plex (that is, some portion of the
volume logical address space is mapped by the subdisk), the subdisk is
considered stale. If the RAID-5 volume is enabled, the association
operation regenerates the data that belongs on the subdisk by using
VOL_R5_RECOVER ioctls. Otherwise, it is marked as stale and is
recovered when the volume is started.
To remove subdisks from the RAID-5 plex, use the following command:
# vxsd dis disk10-01
CAUTION If the subdisk maps a portion of the RAID-5 volume address space, this
places the volume in DEGRADED mode. In this case, the dis operation
prints a warning and must be forced using the -o force option. Also, if
removing the subdisk makes the RAID-5 volume unusable, because
another subdisk in the same stripe is unusable or missing and the
volume is not DISABLED and empty, this operation is not allowed.
Subdisks can be moved to change the disks which a RAID-5 volume
occupies by using the vxsd mv utility. For example, if disk03 is to be
evacuated and disk22 has enough room by using two portions of its
space, use the following command:
# vxsd mv disk03-01 disk22-01 disk22-02
While this command is similar to that for striped plexes, the actual
mechanics of the operation are not similar.
RAID-5 Subdisk Moves
To do RAID-5 subdisk moves, the current subdisk is removed from the
RAID-5 plex and replaced by the new subdisks. The new subdisks are