Do I need to reconstruct my RAID 0?

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.
yhavanna
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Joined: Thu Dec 01, 2011 6:37 pm

Do I need to reconstruct my RAID 0?

Post by yhavanna » Thu Dec 01, 2011 6:57 pm

Hi to all!

I have an external disk which comes in a Raid0 arrange from fabric (G-RAID), with 2 discs 2TB each.
After using it for a while, one day, after re-starting it, Windows could not recognize any format and when re-starting the PC it went into a Checkdisk process. Afther that, disc was recognized but with no acces to it.

I tested some recovery software and I downloaded R-Studio. Right now, I've been able to recover several files on it, with the Extra Know Files as there were almost none recognized with the folder structures. Most of the files in the disk are video files, but many of them seem to be recovered incomplete or damaged as I can not reproduce them, or only the first seconds are reproduced.

So, I have two questions:
First, the video files that I want to recover are Video Files Created by a Nikon D7000, which are *.mov and compressed using MPEG-4 codec.
R-Studio, recognizes them as MP4 Files. Does this change of extension or wrapper, could have something to do with some of the files not being reproduced?
Would it be different if I creat a custom file type for it?

Second, R-Studio recognizes the drive as a single unit of 4TB and when scanning, it was able to read from 0 to 3.78TB (Real size), but as it is a Raid hardware arrangement, how do I know if I need to reconstruct it to get better results? Could the Raid management be failing?
Both discs are within a case and to connect drives separately I would have to strip it down, is it worth it? How can I know?

Best regards and most of all, thanks!

Alt
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Re: Do I need to reconstruct my RAID 0?

Post by Alt » Fri Dec 02, 2011 4:03 am

First, some preliminary notes. RAID0 is suited for temporal data storage only, like system swaps and temporary file storage. Checkdisk is the worst data enemy. When it runs, it may completely ruin data on disks.
Although it's hard to say what had happened with the disk without seeing it directly, I can guess that one of the disks faulted, most likely some "logical" errors, rather than "hardware" faults, which makes chances to recover files rather solid.
I believe, the best way to deal with your problem is to get the disks out of the case and connect them to your computer directly. Then create a virtual RAID0 and process it. You may need to determine the RAID parameters. Our article Finding RAID parameters may help in doing that. Just remember, you don't have to find the checksum blocks, as it's needed for RAID5.
I think, checkdisk might destroy or alter some important information in the file system of the disk, so scanning for Known File Types might be a very useful option for file recovery. Although R-Studio has a built-in mp4 file type, I recommend you to create your own one specifically for your camera. Our article Creating a Custom Known File Type for R-Studio, and our help explains how to add it using the R-Studio graphic known file type editor: Customizing File Types.

yhavanna
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Joined: Thu Dec 01, 2011 6:37 pm

Re: Do I need to reconstruct my RAID 0?

Post by yhavanna » Mon Dec 05, 2011 8:37 pm

Hi! Thanks for the response!

I was afraid of what you mentioned about checkdisk, as when it ray it said something about eliminating orfan registry, several times.
Anyway, I already scanned the disc as a unit 3 times, one with the default parameters and another 2, looking just for some specific video files, the ones built in, and the one I created for my camera.

Several video files were recovered whith the Known files option, but there are still many missing, specially the large ones.
I am attaching here the screens of the scan information I get, it does not seem to be a complete disc damaged. do you think it is worth anyway to open the disk and try the raid0 reconstruction anyway? do you think I might get different results?

Image

Alt
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Re: Do I need to reconstruct my RAID 0?

Post by Alt » Tue Dec 06, 2011 4:27 am

You have a green recognized partition, what does it contain?

yhavanna
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Re: Do I need to reconstruct my RAID 0?

Post by yhavanna » Tue Dec 06, 2011 5:36 am

It contains a few files, video viles, wav files and other adobe projects, which were the last ones written to the disk.
There are the same files both in the Black and in the Green recognized sections.

Alt
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Re: Do I need to reconstruct my RAID 0?

Post by Alt » Wed Dec 07, 2011 5:03 am

Is the size of successfully recovered files larger than 2x(Block size)? If yes, you have found the RAID parameters correctly, if no, most likely you have found the RAID parameters wrong. By saying "successfully recovered files" I mean video files that can be played correctly from the very beginning to the very end.
If the RAID parameters are correct, it might be useful to scan the RAID once again disabling all file systems and leaving only your custom Known File Type.

Once again, I cannot give you more precise advice without looking at the data on the disks.

yhavanna
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Joined: Thu Dec 01, 2011 6:37 pm

Re: Do I need to reconstruct my RAID 0?

Post by yhavanna » Fri Dec 16, 2011 1:24 pm

Hi! Just a post to update in the case. I did ran the scan without searching for any file system and just looking for the custom file type I generated. I succesfully recovered about 2300 video files (about 500 more than te last time), all being able to play correctly, ranging from a few seconds to several minutes.
From what I remember, it seems I have at least 80% of the files back. Alt, thanks for the advice so much!

I am still missing some other files, which were generated by other devices, but I have failed in generating the custom file type for those. One of them, is also a Video file a MTS one, which has a signature at the beginning and doesn't seem to have one at the end. But the problem is that the same bytes at the beginning repeat several times along the file, so when recovering them, each file gets splitted into hundreds! any suggestion for this?

In any case, R-studio has been a great tool for me! Has saved me a lot of money, as I asked for a quote from a specialized recovery service, and they quote me about $2500 USD. It would take about 15 days and they weren't very sure if they could recover more than I had.

Alt
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Re: Do I need to reconstruct my RAID 0?

Post by Alt » Sat Dec 17, 2011 5:29 am

If you can provide me with a short (3-5 sec is enough) of that type of video, I'll try to figure out a workable file type description file. I can't guarantee a success, but this one worth trying.

yhavanna
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Re: Do I need to reconstruct my RAID 0?

Post by yhavanna » Wed Dec 21, 2011 2:10 pm

Hi again,
Alt, thanks for your help!! I uploaded 3 videos 1, 3 and 5 seconds long to yousendit, you can download them here:
http://www.yousendit.com/download/T2dmV ... eVlVV01UQw
Let me know if you need anything else, in case it helps, the custom file type I created and which indeed found the files, but splitted them into several files was:

<FileType id="50004" group="Personales" description="Videos Vixia" features="" extension="mts">
<Begin combine="AND">
<Signature offset="4">G\x40\x00\x10\x00\x00\xb0\x11\x00\x00\xc1\x00\x00\x00\x01\xe1\x00\x00\x00\xe0\x1f\xe9b\xe7c</Signature>
</Begin>
<End combine="OR"/>
</FileType>


Also, in case it helps anyone, the custom file type I created for my videos shot with a Nikon D7000 and recovered I would say almost the 90% of them was:
<FileType id="50000" group="Personales" description="Video D7000" features="" extension="mov">
<Begin combine="AND">
<Signature>\x00\x00\x00\x18ftypqt\x20\x20\x20\x07\x09\x00qt\x20\x20niko</Signature>
</Begin>
<End combine="OR">
<Signature offset="8">\x00\x00\x00\x08NCDB</Signature>
<Signature offset="20">\x3c\x3fxpacket\x20end\x3d\x22w\x22\x3f\x3e</Signature>
</End>
</FileType>

And the custom file type I created for audios recorded with a Zoom H4n was:
<FileType id="50005" group="Personales" description="WAVs H4N" features="" extension="wav">
<Begin combine="AND">
<Signature offset="8">WAVEbext</Signature>
</Begin>
<End combine="OR"/>
</FileType>

Alt
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Re: Do I need to reconstruct my RAID 0?

Post by Alt » Thu Dec 22, 2011 4:28 am

OK. I'll check them out.

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