Recovering from this weirdo Raid 5 Error

Discussions on using the professional data recovery program R-STUDIO for RAID re-construction, NAS recovery, and recovery of various disk and volume managers: Windows storage spaces, Apple volumes, and Linux Logical Volume Manager.
JDHannan
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Recovering from this weirdo Raid 5 Error

Post by JDHannan » Wed Aug 18, 2010 4:50 pm

Okay, so a couple weeks ago I had one of the drives of my 3 Drive Raid 5 die. Suddenly yesterday my computer bluescreened and another hard drive came up as an offline member. I fiddled with it for a bit and got it to come back up as recognizable. However, through doing that, the raid controller apparently lost track of the drive and declared the raid destroyed irreparably.

But, nothing actually happened to the drive. There has been no writing to it, my OS isn't on it and I haven't written anything to it. I bought the R-Studio software and I'm trying to figure this all out.

It seems that the correct order for the drives is Missing, 1, 2... and I did a scan of the 2 drives last night for about 12 hours. Now I've got my virtual raid but it has like dozens and dozens of things under the Device/Disk column like Recognized0, Recognized1, Recognized2, etc etc... the start and size make them overlap crazily and a lot of them have very similar files listed when i double click them.

I tried Recognized0 - which is the only green one - and tried recovering a bunch of files, mostly jpgs, some .PSD, some videos... I tried opening all 95 of the PSD files it recovered, 2 of them opened successfully (but with errors reported by Photoshop) and one of them was a rename of the other one. ALL ninety three of the remaining wouldn't open. Similar stories exist for the jpgs.

It has all the filenames right (for one of the partitions) but the files recovered are trash. What have I done wrong? Is the Virtual Raid drive initially not set up right?

Alt
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Re: Recovering from this weirdo Raid 5 Error

Post by Alt » Fri Aug 20, 2010 12:18 am

When you tried to open recovered jpg files, did they appeared as pictures with blocks messed up, or as nothing?

JDHannan
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Re: Recovering from this weirdo Raid 5 Error

Post by JDHannan » Fri Aug 20, 2010 12:21 am

Most of the jpgs open (in Picasa) saying Invalid Image. Some of them have a working thumbnail, but the picture itself does not work... i'm not exactly sure how that works...

I actually just now had a revelation... maybe I shouldn't be trying to recover this as a raid5 at all... i should be maybe trying to do it as a striped raid between just the two disks i have and not be trying to use a 3rd disk.... but for that matter, you don't need a 3rd disk to recover the data in a 3 disk raid.... crap and i just unplugged the drives...

JDHannan
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Joined: Wed Aug 18, 2010 4:34 pm

Re: Recovering from this weirdo Raid 5 Error

Post by JDHannan » Fri Aug 20, 2010 12:29 am

Okay, i just scanned a very small (like 15 seconds of scanning) portion of the drives (as striped) and it has found a tonne of fully readable files, mostly text and 2/2 jpgs that loaded perfectly

but they have no filenames, they're just enumerated...

any idea why?

Alt
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Re: Recovering from this weirdo Raid 5 Error

Post by Alt » Fri Aug 20, 2010 12:41 am

You MUST recover data from a RAID5 rather than a stripe set, because data blocks are written to the missing disk, too. For example, at the first cycle, data may be written to Disks 1,2, 3-d is used for data parity, at the second one - to Disks 1,3, 2-nd for parity, etc.
Most likely, the RAID parameters are wrong. Maybe, this article could help:
http://www.r-tt.com/Articles/Finding_RA ... ndex.shtml

JDHannan
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Re: Recovering from this weirdo Raid 5 Error

Post by JDHannan » Fri Aug 20, 2010 9:16 am

but remember, i've been running the raid on 2 of 3 discs for a couple weeks, so trying to use the third disk is going to force it to try to use data thats not being used.

and again, you only need 2 of the 3 discs to get all your data anyway, right? I mean obviously thats right because i kept using the computer for two weeks with one disc gone

anyway, the scan finished overnight and the results are poorer than i had expected... the brief scan that i stopped and checked last night seemed to work 100% (but with no file names) but now it has recovered the entire directory structure with absolutely no files somehow... all the files are listed under Extra Found Files with a big red X on it, again they are just numbered, and whats worse is that the files are horribly corrupt :(

could incorrect raid5 parameters really recover all the filenames, portions of each file, but not the entire files?

i tried going through that set of instructions but something went wrong and it didn't find one of the numbers when it should have... but i will try it again

JDHannan
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Joined: Wed Aug 18, 2010 4:34 pm

Re: Recovering from this weirdo Raid 5 Error

Post by JDHannan » Fri Aug 20, 2010 9:39 am

Okay I've run into the problem again with the instructions.

I've got two drives which I will identify by the last 3 characters of their serial numbers: 0TB and RG0

0TB has the MBR at 0
Sectors Preceding: 63
but then it gets weird
Bytes/Sector: 190
Sectors/Cluster: 124

i'm sure those can't be right

RG0 has MBR: 926950
Sectors Preceding: 7536657
/2 = 3768328

I kicked off the search at that offset but its been searching for about 10 minutes and hasn't found it... this doesn't seem right either. :(
edit: it found the NTFS boot sector at sector 65667151 and confirmed the
Bytes/Sector: 190
Sectors/Cluster: 124
Logical clusters: 6124990635755565322

Alt
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Re: Recovering from this weirdo Raid 5 Error

Post by Alt » Sat Aug 21, 2010 11:08 am

Let me think this problem over for a while, OK?

Alt
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Re: Recovering from this weirdo Raid 5 Error

Post by Alt » Mon Aug 30, 2010 5:37 am

Most likely, you set the disk order incorrectly. I think the missing disk should be the first one, then try to find out the parameters of the RAID as you did it before.

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