[Ldsoss] OT: RAID5 recovery issues

[Shane Hathaway]

Richard Smith wrote:
> Well, I've just had a motherboard die on me, in my kubuntu-amd64 system.
> This was after I had managed to recover my RAID array (one member got
> lost..
> somehow no md superblock it said), but before starting to fix some sort of
> upgraded udev weirdness.  This array was housing my music, photos, email,
> etc, all the stuff you don't want to lose. Managed to get things mounted
> and
> checked before I got too tired to continue.  I had set up 4 disks in a
> RAID5
> array, so that I wouldn't lose data if one drive died.  The Hard drives
> were
> old, but the other bits of the computer are less than 18 months old. I
> didn't expect the motherboard to go kaput, and since it's a 754, a
> replacement board is a bit harder to come by.  Oh, it's a software raid,
> made with mdadm, with a LVM group on top of it.  Now, I've got a spare
> system that should POST fine, but it's an old 650 MHZ Athlon, and buried
> somewhere hard to get to.  Would I be able to access this RAID to recover
> stuff, even though the filesystem was set up using tools compiled to run on
> 64 bits?   Has anything similar happened to anyone else, and can you
> give me
> bits of advice?  Also.. if I am able to recover stuff, should I migrate the
> system onto a single drive large enough to house my current system? (raid
> array was nowhere near full when this whole mess started).

Did you ever get a response to this?

Assuming 3 of the 4 drives are still good, you should be in good shape.
 Just plug the drives into a spare box (Intel or AMD, 32 or 64 bit, it
doesn't matter) and boot with an Ubuntu CD.  The system should
auto-detect both the RAID and LVM.  You should be able to copy all of
your files to a removable hard drive.

Linux's software RAID is a real win in this situation, BTW.  Hardware
RAID cards are helpful when disks fail, but they're troublesome when
it's the motherboard that fails instead.

Shane