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

384 Administering hot-relocation
Modifying the behavior of hot-relocation
After the disk that experienced the failure is fixed or replaced, vxunreloc can be used
to move all the hot-relocated subdisks back to the disk. When a subdisk is hot-relocated,
its original disk-media name and the offset into the disk are saved in the configuration
database. When a subdisk is moved back to the original disk or to a new disk using
vxunreloc, the information is erased. The original disk-media name and the original
offset are saved in the subdisk records. To print all of the subdisks that were hot-relocated
from mydg01 in the mydg disk group, use the following command:
# vxprint -g mydg -se 'sd_orig_dmname="mydg01"'
Restarting vxunreloc after errors
vxunreloc moves subdisks in three phases:
■ vxunreloc creates as many subdisks on the specified destination disk as there are
subdisks to be unrelocated. The string UNRELOC is placed in the comment field of
each subdisk record.
Creating the subdisk is an all-or-nothing operation. If vxunreloc cannot create all
the subdisks successfully, none are created, and vxunreloc exits.
■ vxunreloc moves the data from each subdisk to the corresponding newly created
subdisk on the destination disk.
■ When all subdisk data moves have been completed successfully, vxunreloc sets the
comment field to the null string for each subdisk on the destination disk whose
comment field is currently set to UNRELOC.
The comment fields of all the subdisks on the destination disk remain marked as
UNRELOC until phase 3 completes. If its execution is interrupted,
vxunreloc can
subsequently re-use subdisks that it created on the destination disk during a previous
execution, but it does not use any data that was moved to the destination disk.
If a subdisk data move fails, vxunreloc displays an error message and exits. Determine
the problem that caused the move to fail, and fix it before re-executing vxunreloc.
If the system goes down after the new subdisks are created on the destination disk, but
before all the data has been moved, re-execute vxunreloc when the system has been
rebooted.
Caution: Do not modify the string UNRELOC in the comment field of a subdisk record.
Modifying the behavior of hot-relocation
Hot-relocation is turned on as long as the vxrelocd process is running. You should
normally leave hot-relocation turned on so that you can take advantage of this feature if a
failure occurs. However, if you choose to disable hot-relocation (perhaps because you do
not want the free space on your disks to be used for relocation), you can prevent