I had an external USB 2 RAID 1 (Mirror) with two 2TB disks.
The manufacturer is Datacask which is pretty unknown.
The chip used is some Silicon Image chip.
Out of nowhere, I could not mount the raid anymore.
As I cannot believe that both disks failed, I removed them and tried to mount them directly on a SATA port.
I hoped that at least on one disk I can find my data.
Knowing that hardware RAIDs will write some header on the disk I tried to discover/ recover the partition table.
I tried with the testdisk and gdisk utils but none could find a partition table.
I then tried photorec and it could find lots of data.
so in theory the data is there!
Any idea, how I can get a partition table and find out what file system it was using.
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vanthome
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Before running any experiments on the disks, clone them on a new disk, for example with the dd command, and work with the cloned disk only.
I would then insert two new disks in the case just to see whether the controller is still working. If that is the case, copy a single block with known content to the storage at block address 0, then remove the disks again and try to find this block when the disk is directly connected to the SATA port. If you find it you should have the offset for the boot block and you should find the real boot block, partition table etc. at the same location on the cloned disk.
If the controller is not working, inspect the boot block of another disk to see whether there is some unique string on the first few blocks. Most boot blocks of file systems have this. Use this string to search for on your cloned disk.
I wish you luck.....
nn4l
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Thanks :) +1 for clonding before doing anything else (I did that already) – vanthome Sep 17 '15 at 17:33
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The chances to get them directly mounted are quite low. Get the exact same controller you had before, attach one disk (so you still have one in case the controller screws things up) an hope that all raid-metadata was stored on the disk and not on some controller flash memory.
Keep in mind, that Raid1 is not a backup solution, it just creates higher availability of you data, so in such a case you should just use your backup instead of investigating you dead raid controller...
Henrik
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+1 for the idea to get the same controller and try with a single disk. Yea Iearnd that just the hard way that even read cannot guarantee data safety. – vanthome Sep 17 '15 at 17:25