RAID0 Recovery Help

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.
hopeful_dingdong

RAID0 Recovery Help

Post by hopeful_dingdong » Tue Jun 15, 2021 6:50 pm

Hello,

Hoping someone can help me. Yes, I'm a newb. I had a drive array in an external eSATA port-multiplied enclosure with four 1TB SATA drives (WD Caviar Green, if that matters). I got it hooked up to my Mac via PCIe-to-Thunderbolt chassis and could read the array as a MacOS RAID0 disk. I tried copying my files over to a new external drive. It failed any time I left the computer for a while. (dumb-thing number 1: I should have checked my Mac power savings settings, but oh well).

So, I popped the drives in a USB-based enclosure, but (dumb-thing number 2) I didn't realize it was a hardware based enclosure, so it overwrote the RAID partition info on the drives, so now they were no longer recognized as a RAID Array by Mac. I did notice this quickly, and the drive activity LED indicators didn't blink for more than a few seconds on boot-up, so I don't think it did more than overwrite the boot partitions.

Then, I put the drives back in the original enclosure, fired up R-Studio and made "byte-for-byte" uncompressed disk images of 3 out of 4 of them. Drive number 4 would constantly report errors when trying to do so, so I loaded up Disk Drill, which seemingly made it past whatever was hanging up R-Studio, and made a "byte-for-byte" .DMG backup.

Then, I loaded each of those on to a Virtual Block RAID, selected RAID0 but didn't change any other settings in the Parents tab, hit "Scan for Partition" which I cancelled when it looked like it found one - it did. I clicked to View Files on the Recognized0 partition and BOOM! there's all my files! However, the few I tried recovering were unreadable by the relevant software (video, final cut and audio files). I'm now running a "Scan" on the Virtual Block RAID item. It's seeing a lot more information according to the block display, but has a while to go.

My questions are:

- Other than the dumb-things above, did I take the correct recovery steps?
- Should I have done more with the Auto-detect RAID settings (it estimated it would take 3 days to do)
- Can I somehow "repair" the bad sectors or whatever was causing issues with Drive Number 4, then use that repaired image on the Virtual Block RAID for better recovery results?

Any advice would be appreciated. I'm in a bit more of a time crunch than allowing days at a time for processing allows - if I'm taking the wrong steps.

Thanks in advance.

Alt
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Re: RAID0 Recovery Help

Post by Alt » Sat Jun 19, 2021 2:28 pm

My understanding is that you have a pure RAID0 (Striped) level, not RAID10, or alike.

If so, I've got bad news for you: If any of the RAID0 parents has failed, all data on the RAID0 is effectively gone. There may be retrievable some files that fit completely on the healthy RAID parents , but when even a small part of a file resides on the bad sectors of the failed drive, that part of the file is lost.

That's why you have a seemingly good file list, but all recovered files are broken. They, as I understand, are video and audio files, and therefore large.

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Re: RAID0 Recovery Help

Post by Data-Medics » Mon Jun 21, 2021 2:09 pm

There's several possibilities of what could be going on. It could be that you don't have a good clone of that failing disk. Diskdrill is absolute poo in my opinion, so it probably just acted like it was still cloning while just writing garbage to the image file.

A better route would have been to use ddrescue, hddsuperclone, or another linux tool to image the failing drive. Nothing in Windows handles bad sector drives well, period. It's just the nature of how software interacts with the drives in the OS.

It's also possible that your found RAID settings are just a bit off. If you are close on the settings you'll find folder structure, but wrong drive rotation or block size will still throw it off.

Autoscan won't usually accomplish much IMHO, much faster and easier to manually find the settings. Let me know if you want some help with it.

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Re: RAID0 Recovery Help

Post by Alt » Mon Jun 21, 2021 5:42 pm

My understanding is that the platform is Apple's Mac.

Sure, R-Studio isn't the best disk cloning tool, but if it finds a bad sector on a disk, the sector is really bad. You may use some other Linux solutions, but the results will be the same - a lot of bad sectors. You may perform some voodoo tricks to minimize their number, but that requires a lot of experience.

And if a part of a file is sitting on a bad sector of a disk from RAID0, this part is gone. And if this file is a large movie file, this movie is effectively gone, too.

BTW, Disk Drill for Mac is quite a decent piece of file recovery software, as to my experience. It's Disk Drill for Windows that is really poo.

hopeful_dingdong
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Re: RAID0 Recovery Help

Post by hopeful_dingdong » Thu Jun 24, 2021 6:22 pm

Thanks for the advice everyone. Small update:

- I was able to use Klennet RAID viewer: https://www.klennet.com/raid-viewer/ to get an idea of the drive order. Seems like a great tool, btw. It gave me the most likely starting sector and block size. Unfortunately, my four disks weren't able to be lined up like the ideal block map structure, but rather two columns of two drives each were able to zig-zag all the way down. I haven't tried tried a scan on that drive order, because a different order that I ran a full R-Studio scan on allowed me to recover most of the files. However, I'd still like to see if I can retrieve the rest.

- I've plugged in the one drive that didn't get an error-free clone via R-Studio, and am making a new clone via ddrescue, which has about 5 days left. First time through with it only took a day and a half and had 99.51% recovery (4818MB bad-sector and 1 bad area on a 1TB drive).

- I will end up taking that new clone and trying a new scan on the Virtual RAID Block in both the same order that worked last time, as well as the ones that look a bit better from what Klennet reported.

I'll post an update as to how all of that works out, and if anyone has additional advice in the meantime, it's all appreciated. 

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Re: RAID0 Recovery Help

Post by Data-Medics » Fri Jun 25, 2021 5:58 am

Are you sure you were set up as a RAID 0 and not a RAID 10? Check if any drives appear to be clones of each other in a hex editor.

hopeful_dingdong
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Re: RAID0 Recovery Help

Post by hopeful_dingdong » Fri Jun 25, 2021 6:25 pm

Thanks - I did look at the Hex editor and they're definitely not clones. Very odd indeed that it's not RAID10, as the layout sure looks like it (below). Building the Virtual RAID Block in this order and RAID10 doesn't seem to recognize partitions or files, whereas RAID0 with the order I had labeled on the drives originally, does work.
Screenshot 2021-06-25 160745.png
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