RAID Recovery

Thanks for that suggestion. The NewEgg site does list my motherboard as RMA-able. However, it also states that I need all the original packaging to return with it. Unfortunately, I no longer have that.

I submitted a question to them about how we could handle this. We'll see what happens.

David

I like newegg. I returned my motherboard, and they're sending me a replacement. I hope that the new mobo with a working controller will take care of this. We shall see...

David

Well, I'm the proud owner of a new Asus A8N-SLi Premium motherboard. Unfortunately, its behavior looks a lot like my old board. :-(

The hard drives passed all the -*test*-('")s I ran, and I replaced the tables with SATA-II-compatible clip-on cables. I replaced the motherboard and controller. I'm out of parts to replace. I believe that each of the parts is OK, but that the RAID descriptor metadata on my hard drives has been corrupted. (I hope that's all that has!)

So, how can I tell my RAID controller that it should address the four disks as a mirrored and striped array, without wiping all my data?

Thanks,

David

It's a real crap shoot at this point and I'm afraid you're at fairly substantial risk of losing data. Run the RAID setup utility at startup and add drives 1-4 and provide the 10 configuration. Just do not clear the data. If you are lucky, it will rebuild the array and leave the data intact.

I think I'll look into data recovery services *before* doing something that sounds like it may damage my disks further.

Is the danger of data loss that you mention from damaging data in the attempt to rebuild metadata? Or that it's already damaged along with the metadata?

This is something that has been worrying me for some time - in general, what happens to the array if the metadata is damaged? So far as I can tell, the format of the metadata is not documented *anywhere*, nor are any recovery tools, techniques, or procedures. In fact, while the official documentation for this motherboard and the Sil 3114 controller describe how to set up RAID, I have found essentially *no* technical documentation on data formats or recovery procedures.

Now that I need it and can't find it, I have new advice for anyone considering RAID for data protection. Make sure that both the implementation details and recovery procedures are clearly documented; otherwise, don't bother. Using cheap RAID for performance seems to be OK - my NVidia RAID works well and fast - but using it for reliability without that documentation is a losing proposition.

dbr

The plain and simple fact of the matter is that I don't know at this point. As you point out, there is no documentation readily available to assist in the recovery effort. We have not been able to isolate and/or cure the cause of the failure and I am at a loss for what to tell you at this point regarding whether or not the actual data were damaged. I think it is likely that the data are recoverable, but I don't know.

What I do know is that I don't trust mirroring on SATA raids at this point. I have yet to see a successful rebuild after a drive failure, albeit, I have not seen such a failure before your issue. My next build will be SCSI RAID 5, where the technology is quite a bit more mature. Until then, I run RAID 0 and back up religiously. I realize it is no consolation to you at this point, but Acronis makes a very nice product for backing up and restoring SATA raid arrays. I recommend it for anyone running SATA RAID.

Success, at last! I have my data back - most of it, anyway.

I contacted a local data recovery specialist, and he sat down with me to work it out. We did some diagnostics and exploration, too, but here are the significant steps:

1) In the BIOS, delete the RAID set.
2) In the BIOS, create a new RAID-10 set, with the same parameters I used initially.
3) Boot up windows - it recognized the device, but not the filesystem.
4) We ran FileScavenger, a data recovery program. It seems to be pretty versatile - it is designed to recover striped arrays from the individual disks, and to read sectors multiple times if they are failing, and so on. It *easily* found my files - about 250,000 of them, about 365GB.
5) I made room on my NV-RAID to store the recovered data.
6) We told FileScavenger to recover the files into the NVRaid.
7) I examined some of them. Most looked good. Some - a small number of those I examined (one directory) - were garbled. I haven't reviewed all of them yet.

I'm pleased, and am about to reconfigure my Sil array. No more mirroring and striping! I may let the controller just treat this as JBOD, and let Windows stripe a couple of disks together. How well does Windows striping work? I know Linux does a very good job...

Thanks for all your help!

David

Well, I thought I'd try letting Windows stripe it, but it was not obvious when I returned to the management console that Windows would do that. Instead, I'll let the 3114 controller run one striped array, and use the other two disks as single disks - safer.

Any recommendations on chunk and allocation unit size?

Thanks,

David