Data Recovery from ReiserFS RAID Array?

Ruatha asks: "We've recently had a problem with a ReiserFS RAID-5 array - two of the disks failed and, of course, some of the people using the array didn't have backups of their data...Ontrack have returned the disks because they can do nothing with them due to the FS we used on the array. Does anyone know of a company that can deal with data recovery from a ReiserFS RAID-5 array?"

Comments

Re:Responsibility

[foobar104]

Repeat after me, please: The purpose of IT is to help users, not the other way around.

If an employee at this worthy's company lost data, it is the responsibility of the IT department to attempt to recover that data, within reason. That's what the IT department is for. This is a sensitive subject to me, because the IT department at my company closed down the IMAP port on our firewall tonight for what they called "security reasons," despite the fact that (1) we've been running IMAP over that connection for years now, and (2) the connection is encrypted with SSL. It literally took my yelling into the ear of the CTO over the phone, after calling him at home late in the evening, to get this problem fixed. The pervasive attitude of indignant hostility from IT departments in all sorts of industries is really starting to burn me up.

If you worked for me in my IT department, and one of your RAIDs failed, and I had un-backed-up data on it, the only answer I'd want to hear from you is, "Yes, sir, we'll do the best we can and get right back to you." If I even heard a hint from you of the "you were irresponsible so it's not my problem" vein that you showed in your post, you'd find yourself being escorted out of the building carrying your stuff in a cardboard box. And we'd expect you to return the box.

So just keep repeating it to yourself: The purpose of IT is to help users, not the other way around.

Linux FS recovery techniques

[0x0d0a]

Could they have recovered from ext3?

Very likely, yes. Ext2 recovery techniqes are well known, documented, and tools exist (if rudimentary) for recovering files from it. I believe that this translates well to ext3.

Also, if you want someone to recover the data and you're willing to drop some money on it...I strongly suspect that there are people on the reiserfs team that would take on a recovery job quite happily. No one knows reiser better!

That being said, there is currently no good, easy-to-use, powerful recovery tool for Linux filesystems, rather depressingly. Now, you *could* argue that this is because the filesystems are so great, but even so...

You probably know this, but..

[arcade]

First of all, since _two_ disks got screwed at the same time, you've lost the "normal" chance of getting the data back. RAID-5 ensures that if ONE disk fails, you can get the data back due to the parity-stuff - but not if two disks fail. You probably know this.

So, what needs to be done, is to get one of the disks back online again. That *should* be possible, and if nothing really really bad happened, should, i think, in theory, be as easy as getting a lab to pull the disk-platters out and put a new motor / new electronics on them. I'm not sure about this though ;)

Preferrably it could be done by the disk-manufacturer.

You could also check out an excellent company in Norway called IBAS. Check out http://www.ibas.com/america/index.html for their american office. They are really excellent at data reconstruction.

quick fix

[austad]

This may or may not work, however, I've successfully recovered data about 10 or 12 times using this method.

Find a working drive of the same model, take the electronics board off of it and swap it onto the bad drive. Typically when I have a drive fail, it's the electronics, not the mechanical portion of it. So far, this has worked every time for me, one was a Quantum Fireball, and the rest were all Seagate SCSI drives (some FCAL and some ultrawide).

If you had two disks fail at the same time, chances are it's the electronics. Once you recover the data, I would take a serious look at your RAID controller and possibly replace it. I had a bad RAID controller that kept frying drives, and once I replaced it I didn't have anymore problems.

Data Recovery efforts...

[ComputerSlicer23]

Assuming, it's really, really necessary, there are ways of gleaming data off of a drive that has died. You can send your drives off to said company and for a thousand dollars a disk they take it into a clean room, disassmeble the entire platter assembly, physically prepare the platters so they are as good as can be, then put them under their own super duper head assembly.

Assuming you can find one of them, use google for gods sake. Get them to read the drive linearly. At this point, they should be able to put each drive onto new drives for you. Build a raidtab that matches the new drives they give you, do raidstart /dev/mdXX, do a fsck.reiserfs on it. Mount the thing. Poof like magic you have data again.

I've heard of several people recovering Ph.d and masters disertations this way. It's why the DoD has such strict standards about destruction and disposal of a hard drive. It's very difficult to delete data from a drive so it can't be recovered. It's can just get out of control expensive to recover the data.

If it's worth $5-10K, and you can deal without having it for several days, this might actually work... If the company bitches, just tell that it's about what a good tape setup would have cost if they had bought one.

The two guys who said try stripping the electronics are pretty brave SOB's, but that might be worth trying if you can't spring for some experts to deal with that for you.

Kirby