Relocation of disks

[Christian Hansen_2]

Hello,

What's the easiest way to move a harddisk from one slot to another in a MA8000? I do not wan't to change any units, just move the disk to another SCSI channel to get better performance.

[Mohamed K Ahmed]

remove the disk from any raid set or mirror set.
delete the disk from the location
add the disk to a new location (DO NOT INITIALIZE)
add the disk (in the new location) to the raid or mirror sets

Be sure to stop any I/O running on the system (for exampleL shutdown Oracle) so you do not have access to the disks

Also take a full backup just in case someting happens.

Mohamed

[Hein van den Heuvel]

What OS? For example on Tru64 you can readily change device names back (dsfmgr -m) should they change after re-presenting.

I suspect it is not worth it to change.
It could be, but it is pretty rare to have it make a significant effect. Maybe you can explain to us why you think it will make a difference? Is the current bus really at capacity, or just heavily loaded.

Still, The HSG80 Userâ s Guide dedicates a few pages to "Moving Storagesets" around page 3-73. Read all about it!
The indicated procedure will however (best I can tell) recreate a unit and with that create a fresh WWID which in turn will likely create a new lun on our server.

Good Luck,

He

[Mike Naime · Accepted solution]

Christian:

This really depends on if it is a mirorset, or a raidset. Plus, do you have an extra (SPARESET) drive to play with?

If I had an extra drive to play with, I would do one of the following.

Mirrorset:
Set the replacement policy to NOPOLICY.
Increase the membership to 3.
Add the third member.
After the copy is complete, reduce the drive that you want removed.
set your policy back to what you had originally.

This can also be accomplished by having the drive you want added as the only SPARESET disk, and increase the membership. It should autospare in for you if you have set AUTOSPARE ENABLED.


Raidset: This is riskier.
have the drive you want added as the only spareset drive.
Remove the drive that you want moved.
Wait for the raidset to re-build.

There is really no safe way with the raidset to replace this. You are expose while the raidset re-builds.

Mike

[Uwe Zessin]

Hein,
it is possible to delete a unit, storageset and the disks from the controller configuration - then move the disks around and finally add everything in reverse order.

You just leave off the INITIALIZE command to the storageset and the unit will retain the WWID (it is stored in the metadata on the disks). Of course I would re-add the unit with 'DISABLE_ACCESS_PATH=ALL' and then set up the connections.

I have done it several times for Tru64 Unix V5 systems. It worked and we didn't get any new device names.