Re: Imaging Mirrored OS Drives

On Wed, Aug 16, 2006 at 01:05:39PM -0400, andy liebman wrote:
if the imaging software is not too smart and creates the partitions and
filesystems with the exact same size as the original, yes.
(i mean that there should be some space between the end of the
filesystem and the end of the partition to store the md superblock)

quoted

2) Furthermore, if the above is possible, in creating the arrays on the 
new drives is there a way to force mdadm to give the arrays specific 
UUID numbers? It looks like I can do that with mdadm --update? Should I 
create the arrays first using the normal "mdadm -C" procedure, and then 
update the UUIDs?

never tried that, let us know how you fare.

L.

-- 
Luca Berra -- bluca@comedia.it
        Communication Media & Services S.r.l.

Well, I booted with Mandriva One (Live CD), created NEW raid1 arrays 
(md0, md1, md2 and md3) on top of the 4 pairs of partitions 
(/dev/sd{a,b}1, /dev/sd{a,b}2, etc. corresponding to "/boot", "/", 
"swap" and "/home")

      mdadm -C -ayes /dev/md0 -n2 -l0 /dev/sd{a,b}1  and so on...

and when I mounted the md devices all of the data seemed to be there.

Then I stopped the arrays and changed the UUIDs on all the md devices so 
that the UUIDs matched the original UUIDs from the drives that I was 
copying from when I made the images.

      mdadm -Av -ayes /dev/md0 --update=uuid --uuid=xxxxxxxx /dev/sd{a,b}1

I probably could have just created the arrays in the first place 
specifying the uuids.

Anyway, after making those changes, I rebooted and the RAIDED OS just 
came up "like magic".  I was a little worried about whether the 
filesystem would be okay. Rebooted with Mandriva One and ran "e2fsck 
-fv" on all md devices (to force a thorough check and be verbose) and 
all checked out okay as well.

I say, "hmmm". I never expected this to work. Compared to cloning a 
RAIDED OS by doing dd on each drive, partition by partition, this was 
fast! With this approach, it only takes about 15 minutes to produce a 
cloned RAIDED OS.

I'm still worried that something might be wrong, but I can't see what it 
is if it's there.

I promised I would put my "Single-Drive-OS-to-RAIDED-OS" recipe on the 
list. I'll do it tomorrow.

Andy