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Migrating RAID5 to RAID1

Stephen Franken
Occasional Visitor

Migrating RAID5 to RAID1

Hi all,
We have a Compaq Proliant ML370G2 server with a Smartarry 5i RAID controller & 3 x 18GB hot pluggable disks in a RAID 5 configuration (1 logical drive).

We would like to migrate the contents of this LD to a RAID1 LD on 2 spare 18GB drives. The reason for this is to allow us a "fallbak" plan i.e. to eject one of the disks in the mirror before we make changes to the server (pacthes, SPs). If a SP breaks the server we can just boot from the "known good" disk as a backout plan.

I have a procedure in my head but wanted to get some opinions in case I've missed something:
1) Take ghost image of existing LD on RAID 5 array (to network location)
2) Remove the 3 x 18GB drives
3) Insert the target 2 x 18GB drives
4) Erase the Smartarray config
5) Create a new RAID1 array and LD using the 2 x 18GB drives
6) Ghost the image back down to the new LD (the data size on the existing LD is less the capacity of the target LD so no probs there)

If all goes wrong, my backout plan to get the RAID5 array back up is:
1) Erase Smartarray config
2) Eject the 2 x 18GB drives
3) Insert 3 x 18GB drives
4) Boot server & allow the RAID controller to grab its config from the 3 x 18GB drives

I'd really appreciate anyone's thoughts on this as I *REALL* don't want to have the rebuild the server again from scratch!!

Thanks in advance,
Steve Franken.

Terry Hutchings
Honored Contributor

Re: Migrating RAID5 to RAID1

This procedure sounds like it will work, but I don't see any mention of how much space is being used in the raid 5. Obviously, if you have over 18 GB of data on the raid 5, then you will not be able to restore the image onto a mirror of 2 18.2 GB drives.
The truth is out there, but I forgot the URL..