General :: Data Recovery For Overwritten Partition

While attempting to install FC12, Anaconda took it upon itself to overwrite the partition on my backup disk. Now I need to figure out if there's a way to get at least some of my data back. If there's a better place for this question, please let me know and I will happily move it. Using Linux since 1993, other Unixoid systems since 1986. I bought this machine back in 2004 or so. It was a pretty decent machine back then, but it's showing its age now: 370Mb of RAM, 2 hard disks with 80Gb and 120Gb (I don't think the other specs are relevant, but just let me know if I'm wrong). In a fit of insanity, I decided to install Gentoo on it. Don't get me wrong: I love certain things about Gentoo. But the constant fiddling that's required, while it can be fun at first, gets old kinda quick.

So various and sundry things have been going wrong with it here and there (CD-ROM, sound card, etc ad infinitum), and, finally, it wouldn't even load X any more (almost certainly some final Gentoo update which broke something) and I said "screw it, I'll just put Fedora on it." This is what I use at work, and plus I have a good friend who has far more patience with admin stuff than I do and Fedora is what he knows. So, last night, I pick up an FC12 CD that I have lying around and decide to finally just reinstall the whole thing. I went so far as to buy myself a Passport USB drive, 319Gb, and have been backing up up all my stuff very regularly to that drive. I go through one final cycle of backing up and verifying before I start the reinstall.

So my drive is solid, and contains everything I could possibly need (and probably quite a bit of stuff I don't). After booting into FC12, I used Palimpsest to explore the partitions on the existing hard disks. Not sure which was which, I mounted the Passport, where I have cleverly saved a copy of my fstab. Using this, I can see which of my partitions were /boot, /, /home, etc. Most of my personal data has been put into separate partitions so that I could reinstall without blowing away the data. I hope that I can do that there, but, if I can't, no matter: I have a backup. I find some bits of empty space and delete a few of the partitions and recreate them, consolidating the empty space. Still confident in my backup, of course.

So I run Anaconda. Nothing happens. Eventually, I figure out that it won't run the graphical interface because I don't have enough memory. I can use the text version, no biggie. It gets to the part about the disks. I tell it which hard disk to install itself onto. For some reason I think it's going to pop up and ask me about the existing partitions and whether I want to keep them or rewrite them (maybe that's a previous version of Anaconda? or a different installer altogether, who can remember). It does not. It babbles something at me about LVM (which I've personally never really used before), and then promptly locks up. Obviously standard Fedora on a low-RAM machine like this is doomed to failure.

I poke around on the Internet, and I eventually stumble on the Fedora "spins" and select FC13/LXDE. Hopefully this will have better luck. Reboot with the new CD, take a look at my hard disks. It has completely overwritten the old partitions, replacing them with LVM partitions. But not a big deal: I have a backup. Take a look at the Passport. Its ext2 filesys has also been replaced with an LVM partition. Proceed to beat head against wall. So, obviously what happened is, since I (foolishly) had the backup drive mounted at the time I ran Anaconda, it assumed I wanted it to take over that drive as well, and just formatted everything it could lay hands on as LVM. It certainly never asked me my opinion on the matter.

But, fine, I shouldn't have had it mounted. The question is, what do I do now? My first, panicked instinct, was to just set the partition type back to 83 (I believe LVM is 8E), which I did (using cfdisk). That might have made it worse; I dunno. But I'm pretty sure I haven't written anything else to the disk since then. I've tried testdisk (nothing useful; although it can seemingly find the underlying deleted partition, it won't actually do anything with it), and a bevvy of Windows Linux recovery programs (Stellar Phoenix, DiskInternals, Raise, and R-Linux), all of which were completely useless except for R-Linux, which scanned the disk for eight hours and was still going when I had to interrupt it (I may come back to that one, but so far it doesn't look too promising).

My primary problem is that I can't make an image of the disk because this little Passport is the biggest hard drive in the house. I would certainly feel better if I could image everything off it and then play with the image. But, of course, it doesn't matter that very little of that 319Gb was actually being used: I still need 319Gb worth of space to make an image. I ordered another (larger) Passport, which should be here Wed. Once I have that I believe I can do something like so:
Code:
dd ifs=/dev/sdX ofs=/mnt/bigpassport/smallpassport.img bs=512
Right? Then I can muck about with that image in some amount of safety.

Of course, I also have the original hard drives, which are not so large. testdisk can identify the original partitions on those too, but, again, won't actually do anything with them. If I could find something that would image just the partitions I care about, I could probably save those as well, but I don't have any other external hard drives with 120Gb of space free. Can I somehow take the info that testdisk is giving me about those original partitions and use dd to get only that part of the image? Are there other recovery tools I haven't considered? I have a Windows (Win7) laptop, a Linux laptop (FC10, I think), although its power cord is flaky so it's not too reliable, a smaller Mac, a really old Windows box (XP on it, I think), and this formerly-Linux box, which I can only boot off CD's at this point. There's nothing on this disk worth the 500 bux that professional data recovery would charge me, but it's worth a day or two of my life to try to get at least some of it back.