Sign in with
Sign up | Sign in
Your question

Data recovery from a failed RAID5 array?

Last response: in Storage
Share
April 14, 2012 2:08:12 PM

Hello everyone,

I have quite a serious issue with my RAID5 array. It is made of 3 1TB Western Digital enterprise storage grade disks, somehow a problem would happened every now and then : one disk (always the same I believe) would not be detected at boot, then I had to reboot one time or two and it would be detected again and it was rebuilt, it didn't bother me too much as I thought that anyway if this disk was to fail I would just have to replace it, well too bad things didn't happen that way. My computer rebooted automatically one night because of those god-damned windows update and now it can't detect that disk anymore and the status of the array is failed !

This is strange because prior to this I still could access the array (and back up data...) if one of the disks was off. Since a SMART test tells me that the disks are all fine I assume the problem was caused by the motherboard or the raid chipset on it.

My fear is that there was a two disk failure case : one failed when it was needed to rebuild the rest, but maybe not and I hope not, but there's no log at all so we can't know anything (this is pretty stupid I can't believe there aren't logs, maybe I just can't find them?). Anyway the data can't have vanished, nothing was formatted, nothing was written on those disks since and the disks are functional, so it is here even if some may have been damaged.

It was careless of me to let this thing go on and now I may have lost very valuable data :sweat:  Seems like we should always expect the worst... it's also pretty irritating to think that I probably wouldn't have had any problem if I hadn't use RAID5 : false sense of security...

I have bought a new motherboard to avoid having to deal with the old one anymore when I'll be done with the data recover, I also bought a new 1TB hard drive to back up the one who's allegedly faulty : the Intel storage manager allows me to reset that disk or something like that, I don't know what it means, but it most likely means formatting it maybe to rebuild the rest, but what if the data needed to rebuild is not on the 2 other disks... so if I'm going to try that I will clone that disk with ddrescue on my new one.

Do you know if there is any software to "emulate" a raid for data recovery (like you chose the 3 back up images of your disks and the software allows you to mount them in raid 5) ?

I'm pretty lost here and I have to be extra careful not to make things worse...

Any help on how to recover data from a failed RAID5 array is very welcome.
a c 311 G Storage
April 14, 2012 3:14:08 PM

It really depends on the cause of the failure, if two disks died you have a big problem, but it it was just one or the controller or controller software then you have a chance of recovery. I would try this first (and not write anything to the disks): http://www.freeraidrecovery.com/library/raid5-recovery....

Now you know why storage guys always say that RAID is not a replacement for backup, it is simply fault tolerant storage.
!