VERITAS Volume Manager 3.5 Administrator's Guide (September 2002)

Configuring Hot-Relocation to Use Only Spare Disks
238 VERITAS Volume Manager Administrator’s Guide
Configuring Hot-Relocation to Use Only Spare Disks
If you want VxVM to use only spare disks for hot-relocation, add the following line to the
file /etc/default/vxassist:
spare=only
If not enough storage can be located on disks marked as spare, the relocation fails. Any
free space on non-spare disks is not used.
Moving and Unrelocating Subdisks
When hot-relocation occurs, subdisks are relocated to spare disks and/or available free
space within the disk group. The new subdisk locations may not provide the same
performance or data layout that existed before hot-relocation took place. You can move
the relocated subdisks (after hot-relocation is complete) to improve performance.
You can also move the relocated subdisks off the spare disks to keep the spare disk space
free for future hot-relocation needs. Another reason for moving subdisks is to recreate the
configuration that existed before hot-relocation occurred.
During hot-relocation, one of the electronic mail messages sent to root is shown in the
following example:
To: root
Subject: Volume Manager failures on host teal
Attempting to relocate subdisk disk02-03 from plex home-02.
Dev_offset 0 length 1164 dm_name disk02 da_name c0t5d0.
The available plex home-01 will be used to recover the data.
This message has information about the subdisk before relocation and can be used to
decide where to move the subdisk after relocation.
Here is an example message that shows the new location for the relocated subdisk:
To: root
Subject: Attempting VxVM relocation on host teal
Volume home Subdisk disk02-03 relocated to disk05-01,
but not yet recovered.
Beforeyou move any relocatedsubdisks, fixor replace thedisk thatfailed (as described in
“Removing and Replacing Disks” on page 76). Once this is done, you can move a
relocated subdisk back to the original disk as described in the following sections.
Caution During subdisk move operations, RAID-5 volumes are not redundant.