[svlug] How to un-raid an raid/mirror?

Scott Hess scott at doubleu.com
Sun May 4 12:33:23 PDT 2003

On Wed, 30 Apr 2003, Jos Laake wrote:
> I have the opposite problem.  I am wondering if there is a way to set up
> RAID-1 mirroring on an existing system without it. I have a second drive
> identical to the first one.  Is there some way to just copy the drive
> and then go RAID-1 from there?

Setup the new drive as a RAID-1 array with a single device.  Build a 
filesystem on it, copy everything over.  Then, taking a deep breath, add 
the original drive as a new spare and it will rebuild the array on it.

One caveat is that you should make certain that the disks really are
identical (fdisk -l should tell you what you need to know).  Even the same
model number isn't necessarily always identical, depending on which
assembly line it came off, or when.  If they are different, before
embarking on the above make certain that you start building the RAID-1
array with the smaller device (or partition things so that you can do that
later).  Otherwise you'll try to add the original drive as a spare and
find that you can't.


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