Veritas Volume Manager 5.0 Administrator's Guide (September 2006)

382 Administering hot-relocation
Moving and unrelocating subdisks
# vxassist -g mydg move home !mydg05 mydg02
Here, !mydg05 specifies the current location of the subdisks, and mydg02 specifies
where the subdisks should be relocated.
If the volume is enabled, subdisks within detached or disabled plexes, and detached log or
RAID-5 subdisks, are moved without recovery of data.
If the volume is not enabled, subdisks within STALE or OFFLINE plexes, and stale log or
RAID-5 subdisks, are moved without recovery. If there are other subdisks within a
non-enabled volume that require moving, the relocation fails.
For enabled subdisks in enabled plexes within an enabled volume, data is moved to the
new location, without loss of either availability or redundancy of the volume.
Moving and unrelocating subdisks using vxunreloc
VxVM hot-relocation allows the system to automatically react to I/O failures on a
redundant VxVM object at the subdisk level and then take necessary action to make the
object available again. This mechanism detects I/O failures in a subdisk, relocates the
subdisk, and recovers the plex associated with the subdisk. After the disk has been
replaced, vxunreloc allows you to restore the system back to the configuration that
existed before the disk failure. vxunreloc allows you to move the hot-relocated
subdisks back onto a disk that was replaced due to a failure.
When vxunreloc is invoked, you must specify the disk media name where the
hot-relocated subdisks originally resided. When vxunreloc moves the subdisks, it
moves them to the original offsets. If you try to unrelocate to a disk that is smaller than the
original disk that failed,vxunreloc does nothing except return an error.
vxunreloc provides an option to move the subdisks to a different disk from where they
were originally relocated. It also provides an option to unrelocate subdisks to a different
offset as long as the destination disk is large enough to accommodate all the subdisks.
If vxunreloc cannot replace the subdisks back to the same original offsets, a force
option is available that allows you to move the subdisks to a specified disk without using
the original offsets. Refer to the vxunreloc(1M) manual page for more information.
The examples in the following sections demonstrate the use of vxunreloc.
Moving hot-relocated subdisks back to their original disk
Assume that mydg01 failed and all the subdisks were relocated. After mydg01 is
replaced, vxunreloc can be used to move all the hot-relocated subdisks back to
mydg01.
# vxunreloc -g mydg mydg01