Try to recover a 12TB partition from a RAID5 Array

How to use TestDisk to recover lost partition
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jlimbo
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Joined: 12 Nov 2012, 00:33

Try to recover a 12TB partition from a RAID5 Array

#1 Post by jlimbo » 12 Nov 2012, 01:20

I was expanding a RAID 5 array when I had a power cut. When the power came back on, the expansion operation continued automatically and I'm now trying to recover the 12TB of data that was stored on it in a single partition.

I have run the analysis and written the parition table, but there's no change after the requsted reboot. The disk still shows as RAW and not formatted with the NTFS partition.

Am I missing something? Can someone point me in the right direction?

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Fiona
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Re: Try to recover a 12TB partition from a RAID5 Array

#2 Post by Fiona » 12 Nov 2012, 08:09

//I've removed your crosspost

How did you expand your partition?
Did you use your disk management console?
Is your Array still intact?
Did you check your disk controller?
How ist your array listed in your disk management cosole?
Some info about your OS and previous size of your partition are appreciated also.

Fiona

jlimbo
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Joined: 12 Nov 2012, 00:33

Re: Try to recover a 12TB partition from a RAID5 Array

#3 Post by jlimbo » 12 Nov 2012, 09:38

Thanks for removing crosspost, accidently submitted before edit and though I'd stopped it in the nick of time. Doh!

It's hardware RAID through a Highpoint card so expansion was done with the built in utilities.
Haven't done anything with the disk mmc other than check the availability of the drive. Its there showing the expanded array as unallocated.
The RAID Card utilities indicate the array is intact and I've run the verification test to make sure. I've been in contact with Highpoint and they seem pretty sure the card is ok.
OS is WIndows Home Server 2011 and partition was 12TB in size.

Thanks
John

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Fiona
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Re: Try to recover a 12TB partition from a RAID5 Array

#4 Post by Fiona » 12 Nov 2012, 10:11

An appropriate solution I could offer would be;
Did you use your array as one partition?
Did you create your lost partition using windows disk management console?
Easiest solution at the moment would be, to create an unformatted partition exactly like before.
If you'd format it, you'd override your previous file system and TestDisk wouldn't be able to recover it anymore.
So, don't format anything
Using datarecovery software on a 12 TB array, the scan would last ages.
That's why I ask, would it be possible to create an unformatted partition exactly like before?
Afterwards, you can have a try to rebuild a boot sector which could make your data visible.
The try to rebuild your boot sector is intended as a diaganose first.
So there will be no change to your disk, except your created empty partition.
It will give you the opportunities either to copy your data or write your boot sector to make your data accessible.
Creating a GUID partition table doesn't touch any data which are underlying in your sectors.
I assume, it was a GUID-partition, because MBR ist limited to 2.2 TB.
If you used 4 KB sector size to increase MBR-Limit, please let me know.

Fiona

jlimbo
Posts: 4
Joined: 12 Nov 2012, 00:33

Re: Try to recover a 12TB partition from a RAID5 Array

#5 Post by jlimbo » 12 Nov 2012, 12:18

Array was indeed a single partition occupying the entire array
Yes I did use DIsk Management Console to create it and it is GUID
A deep scan took 17 days btw, it finished last night, but the lost partition starts at cylinder 13 so a quick search finds it pretty quickly
I've managed to rebuild the boot sector and rewrite the partition table. However, on the Repair MFT page it say both MFT and MFT Mirror are bad and cannot be repaired. I've rebooted and the result is the anaysis page says there's no FAT, NTFS ext2 etc marker. If I try to rescan, testdisk hangs

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Fiona
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Re: Try to recover a 12TB partition from a RAID5 Array

#6 Post by Fiona » 14 Nov 2012, 16:20

If TestDisk hangs, indicates normally a damaged file system.
I've rebooted and the result is the anaysis page says there's no FAT, NTFS ext2 etc marker.
If your partition is available in your partition table, you can use the menu Advanced and Type to add your file system NTFS to your MS Data-Partition.
Afterwards you can use the menu Boot to have a try to rebuild your boot sector.
Rebuuilding your boot sector doesn't damage anything.
It's for diagnosis purposes only.
That's why "Write" is not recommended yet.
Please have a try to list your data first.

Fiona

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