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Hosed the Partition Table of my Drive - any suggestions?

post #1 of 2
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I need help rescuing my data of my 5TB RAID which is connected via iSCSI.

The RAID itself is running fine, but due to a PEBKAC-Error, I managed to delete the partition table of the array. In theory, this shouldn't be too much trouble: Simply write a new partition table to the disk.

Here are the steps I've already taken:

*) I followed this Tutorial here, and testdisk can find the RAID and get a proper readout of the Size (5001GB, aka: 5 TB).

But there seems to be something wrong with the blocks, see here:


It reported 4294967295 blocks. At my first try I confirmed this, and went ahead.

*) Searching for the partition, here is what it found:


The HFS partition starts at sector 399528 since the obligatory 210MB EFI-Partition is in front of the Data-Partition. I then started pdisk and entered the values found using testdisk according to the Tutorial.

*) This left me with this result:


Of course, it also failed to mount the 600GB Partition.
The amount of blocks (4294967295) must've been wrong, since 4294967295 equals about 2,2TB.

*) I then used Data Rescue 3 to confirm that the files are still there. After about 48 hours of Deep-Scanning the RAID, all of the Files could be found, but I could not use them since they were garbled - Jpegs were cut off in the middle, for example.


I took the amount of blocks from Data Rescue 3, started pdisk again, and entered the amount of blocks (9.767.587.840) when I was asked for the size of the disk, see:




But the size is still incorrect.

Searching for a GPT-Partition, testdisk gave me this:


So I added the amount of free disk space to the size of the partition (4.294.567.767), but still, no luck.
All it would take is to enter the right values in pdisk to create 1 small EFI-Partition and one big HFS+ one, but I can't seem to get it right for the life of me.
Any ideas?
Now running on a 20" aluminium iMac (Fall 2008), as well as a Macboook Pro 13" (mid 2009) and an iPhone.
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Now running on a 20" aluminium iMac (Fall 2008), as well as a Macboook Pro 13" (mid 2009) and an iPhone.
Reply
post #2 of 2
Quote:
Originally Posted by Denmaru View Post

I took the amount of blocks from Data Rescue 3, started pdisk again, and entered the amount of blocks (9.767.587.840) when I was asked for the size of the disk, see:

But the size is still incorrect.

pdisk seems to be topping out the partition size at the CHS (cylinder, head, sector) size reported by testdisk despite testdisk measuring the size correctly at 5TB. The example tutorial only had one drive, not a RAID set and you can see the CHS size matches the measured size correctly.

The CHS size should really be something like the 9.767.587.840 figure but it may be to do with the way RAID is handled. You can try running pdisk with the -c option so that it ignores the listed device size in the partition table when creating a partition.
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