Rebuilding a partition table after failed resize

So. When I decommissioned my NAS, I moved stuff off the drives incrementally. My RAID5 media partitions were the first to get nuked, and I reformatted that partition on one of the drives as an NTFS partition, for use on my desktop. I then moved my pictures off the RAID 6 onto that NTFS partition, and wiped the RAID6 partitions.

I ended up with 500GB of unallocated space, followed by 1.36TB of a NTFS partition with my pictures on it. So I wanted to make use of that 500GB of space. So I tried in in-place extension of the free space. Windows Disk Management didn’t allow it, so I tried GParted, and GParted worked. I now had a 1.86TB partition. I unplugged the drive and packed up for Canada, without testing it.

Now, I’m in Canada, and have discovered one crucial thing: GParted didn’t move/copy the NTFS data structures backwards, so the partition is unrecognizable. (Why it allowed this is a question I haven’t tried to answer, but might in the future.)  I haven’t reformatted the drive, so I should be able to get everything back if I rewrite the partition table back to its original state.

Problem is (when is anything ever simple) I don’t have a record of the partition table. I know I set it up as 500GB in one partition, and remaining space in the second when I first installed Fedora. But I don’t have the exact partition boundary. Thankfully, because I have a backup (with Crashplan, who I’m still annoyed with), I won’t have any data loss. But I’d prefer not to redownload 700+GB of pictures, so onward with mucking around with partition tables instead!

First off, data recovery is not what I’m looking for. So PhotoRec, which I remember using with good experiences, is out. (As is PC Inspector File Recovery.) What I’m trying to find is either a partition recover program, which would automatically recover everything, or a partition identifier program, which I could then use in conjunction with manually editing the partition table (yay parted, or alternatively, hex editors!).

Googling “Partition recovery software” gave me a few programs, most of which I ignored because they appeared to be the general commercial file recovery programs that scan your drive and attempt to detect files based on their headers.

I did find TestDisk – which is completely freeware, Active Partition Recovery – DOS version is freeware, Windows you have to pay for, and Find & Mount – crippled freeware, speed is limited to 512KB/sec.

So I started off with TestDisk, and ran that for a while. Then I interrupted it and restarted it, thinking I had passed the wrong options to it. And then I let it run for a while, but it still didn’t find anything, so I interrupted it to shutdown everything to fly to Halifax.

Which is where I am right now, without the drive, which is still in Waterloo. But I can plan a course of action – something which is probably better than trying stuff when I have the drive in front of me.

So my plan is to try TestDisk, get it to run the deep scanning method to try and discover the start of the NTFS partition boundary. I’m going to see if I can find an option that will specify searching from the 499GB mark onwards, since I’m quite sure the boundary’s at the 500GB mark. (There’s a step by step guide on the Testdisk wiki, but no mention of command line options.) If I can’t, then I’ll let Testdisk run overnight and see if that finds anything.

If that fails, I’m going to look at the Active Partition Recovery and see if the free version will show me the partition boundary so I can manually create the partition again.

If that also fails, then I’ll run Gpart, and see if that does anything.

Of course, the final thing to do would be to use parted to create a 500G partition, and then a partition that uses up the remaining space. And if that doesn’t work, run the Fedora installer again and try recreating the partitions, being very careful not to select the ‘format’ option.

I also found a few programs that I’ll try to remember if/when it comes to other hard drive stuff:

Gpart – guesses at partitions based on content of the hard drive. HOWTO here, but it’s old and I’m not sure how relevant it still is.

NTFSfix/NTFSresize – Both part of the ntfsprogs package, which itself was merged with ntfs-3G. Comes with Linux distributions.

PartedMagic, a free bootable cd that is essentially a linux distro in itself, and comes with a bunch of tools pre-installed.

MHDD, a free program that sounds interesting and is aimed towards diagnostics on the drive hardware itself, rather than filesystems and data on the drive.

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