Raid 1 and disk images

[TomC]

I am trying to learn more about procedures for backing up "hardware" RAID 1
arrays. I am specifically interested in the functionality of the RAID
controller on the Asus PSCH-LR motherboard, but I don't intend this question
to be restricted to that case.

From my experience with other hardware RAID controllers, I believe that
performing the steps below will not restore a hardware RAID 1 (mirrored)
array.

1. Make a Ghost or other image backup of one of two drives in a mirrored
array.
2. Remove both hard drives.
3. Replace them with new drives of the same type as the first two.
4. Restore the Ghost image to one of the drives.
5. Tell the RAID controller utility to rebuild the array using the data from
the restored drive.

If this won't work, why not? It sure would be convenient if it worked.

 

[David H. Lipman]

From: "TomC" <[email protected]>

| I am trying to learn more about procedures for backing up "hardware" RAID 1
| arrays. I am specifically interested in the functionality of the RAID
| controller on the Asus PSCH-LR motherboard, but I don't intend this question
| to be restricted to that case.
|
| From my experience with other hardware RAID controllers, I believe that
| performing the steps below will not restore a hardware RAID 1 (mirrored)
| array.
|
| 1. Make a Ghost or other image backup of one of two drives in a mirrored
| array.
| 2. Remove both hard drives.
| 3. Replace them with new drives of the same type as the first two.
| 4. Restore the Ghost image to one of the drives.
| 5. Tell the RAID controller utility to rebuild the array using the data from
| the restored drive.
|
| If this won't work, why not? It sure would be convenient if it worked.
|

Sounds like it will work except step #3. It doesn't have to be the same tyope as the first
two. For example, it can be a larger capacity.

Depending on the way the mirror works, you may have to break the mirror prior to imaging the
mirrord pair. Norton/Symantec Ghost does have a disclaimer about its use with RAID.
However, annecdotal information under certain circumstances have indicated that it can be
done especially if the RAID is done by the controller and not created by an OS.

 

[TomC]

David;

Thanks, but my question was intended to take the type of hard drive out of
the equation, by having all drives identical. I am aware of the Symantec
Ghost disclaimer, that basically says "it might work". That means that
Symantec found that it sometimes did NOT work, and in fact the procedure I
described did not work for me using a 3ware controller card. If I understood
RAID a bit better, and knew what RAID info was stored on the hard disks and
what was stored in the controller's memory, maybe I could predict what would
work and what would fail.

Tom