Sometimes /etc/vx/bin/vxunreloc may not succeed due to missing original location information.  This document is intended to help locate where the disk originally resided.  It also addresses how to control where it gets relocated.

Normally, to unrelocate a relocated subdisk, you just run:

/etc/vx/bin/vxunreloc [-f] [-g diskgroup] [-ndm_name]  dm_name

For example:

# /etc/vx/bin/vxunrelocdisk03

will move all the hot-relocated subdisks on disk03 back to the repaired disk.

During the original hot-relocation, if a relocation procedure of a failing/failed disk was successful and recovery has begun, the following mail message is sent to root:

Volume v_name Subdisk sd_name relocated to
newsd_name, but not yet recovered.

This is useful information when it becomes necessary to unrelocate a relocated disk.

By default, vxrelocd sends mail to root via mailx with information about a detected failure and the status of any relocation and recovery attempts. It might be a good idea to send mail to an additional user to have a back-up copy of the original subdisk information.  

nohup vxrelocd root &

and you want mail also to be sent to user1 and user2, change the line to read:

nohup vxrelocd root user1 user2 &

Alternatively, you can kill the vxrelocd process and restart it as vxrelocd root user1 user2, where user1 and  user2 are the users' login names. Do not kill the vxrelocd process while a relocation attempt is in progress.

Additionally, when a subdisk is hot-relocated, its original disk media name is stored in the "orig_dmname" field in the configuration.  "Before" you run the vxunreloc command, you can do a search on this field to determine the subdisks that originated from a failed disk as follows:

# vxprint -mvphrsg dgname |egrep '^sd| orig_dmname'

To help control where a subdisk gets relocated, you can use "spare" and "nohotuse."  Marking only certain disks as "spare" makes those disks available first for relocating failed subdisks.  Disks that are marked as spares are not used for normal allocations unless you explicitly specify them. This ensures that there is a pool of spare space available for relocating failed subdisks.  When a disk is marked as "nohotuse," this excludes the disk from being used by vxrelocd, but it is still available as free space. See the vxedit(1M) and vxdiskadm(1M) manual pages for more information on marking a disk as a spare or nohotuse.

Another piece of information which may be helpful in locating original disks/subdisks is knowing the relocation policy.  To determine which of the eligible disks to use, vxrelocd first tries the disk that is closest to the failed disk. The value of "closeness" depends on the controller, target, and disk number of the failed disk. A disk on the same controller as the failed disk is closer than a disk on a different controller; a disk under the same target as the failed disk is closer than one under a different target.