[sdiy] OT: how to save a dead Raided Drive?

[Andre Majorel]

On 2009-06-27 01:28 +0000, Dan Snazelle wrote:

> my 3yr old 500 gig lacie ext hard drive died. (and no, i had not
> backed it up...money for a new drive had been non-existent)
> 
> now since it is 2 WestDigital 250gig drives in the box, i am
> assuming it is a raid setup with a disk controller card of some
> kind
> 
> BUT then i wonder, if i get these drives into their own new
> enclosure, since they were in a RAID array, how do i get the
> computer to read them properly?

If it can hold 500 GB of data using two 250 GB drive, it's RAID-0
a.k.a. striping which is really more AID than RAID since there's
no redundancy.

Best case is that the controller or PSU died. In that case, you
can put the drives in a computer and read the data off them. The
easiest is probably to get a computer with enough SATA or IDE
ports to plug four drives at a time ((a) the one where the system
is installed, (b) and (c) the two from the LaCie thing and (d) the
500 GB+ one you'll have to find the money for) and copy the data
from disks (b) and (c) to disk (d). If LaCie used concatenation,
it'll be easy (cat /dev/sdb /dev/sdc >/dev/sdd). If they used
striping, you'll have to first find out what the stripe size is
then use something along these lines :

  http://www.teaser.fr/~amajorel/misc/unstripe

If the failure is not in the controller or PSU but in one of the
disks, either they used striping and you're SOL, or they used
concatenation and then you may be able to recover some data.

> it is very unlikely that both drives would mechanically fail at
> once right?

Yes, though I've seen drives from the same batch fail a couple
days apart, while installed in different computers. Another thing
than can and does happen is catastrophic failure of the PSU
frying both disks at once.

Don't try writing to disk (b) or (c). That could easily get you
into deeper... waters. Get advice from knowledgeable people,
like comp.sys.ibm.pc.hardware.storage.

-- 
André Majorel <URL:http://www.teaser.fr/~amajorel/>