On Fri, Jul 27, 2001 at 12:46:50AM -0700, Karsten M. Self wrote: | on Fri, Jul 27, 2001 at 12:26:35AM -0400, dman ([EMAIL PROTECTED]) wrote: | > | > I screwed up my partition table today and, like an idiot, I don't have | > a record of it. Are there any tools I can use to determine where my | > partitions were? | | No specific tools I'm aware of. I keep a hardcopy printout of my | partition tables and mount schemes, backed up by my paritioning HOWTO | (doing double-duty as another backup of my partition tables).
I will definitely have a hardcopy backup after I get it fixed! | > I have a 10GB IDE disk, hda. I had hda1 as /, hda2 as swap and hda3 | > as /home. The space was approximately evenly divided between / and | > /home and 256MB swap. Obviously / starts at sector 1. I determined, | > through trial-and-error, that / ends not before sector 748, but fsck | > doesn't complain if I make the partition too big. I don't think I | > have the size quite right because when I add 256MB to that and | > allocate /home I get errors about an invalid superblock. I can run | > debugfs on / and see all the data in that superblock. There must be | > some way (even looking at the raw bits on the disk) to determine where | > the partitions started prior to my screw up. It is (was) a woody | > system and I have potato CDs (ie rescue disk). | | I think the following may work. I've managed to recover a partition | table from memory before. | | If you know how you sized your partitions, you can try plugging in the | appropriate values, and saving the table. Since the partition table | doesn't actually modify disk data, this won't scramble your data. I'd | restrict my mounts to read-only -- if you size things right, your | filesystems should match up, if you don't, they should break. That's | the theory. | | It's a bit seat-of-your-pants, and it's a last-ditch suggestion, and | it's crazy, but it might just work.... It worked, more-or-less for the first partition. I knew where it started so it was just a matter of finding the end. The problem is, neither mount nor fsck seem to care if the partition is too big, only if it is too small. I found the minimum size it must be for no complaints (1 sector smaller tells me that the super block says the partition is bigger than it really is). I am not sure that it is the right size because when I add in the swap size (I remember that was 256MB, though I'm not as certain anymore) to determine where the third partition starts, it doesn't work. I was hoping that there was some tool to (at the very least) give me a raw dump of a certain section of the disk that with a bit of RTFM on ext2 I could determine where the superblock (start of partition) is. (If you have a partition with a valid super block, run 'debugfs' on it and type "stats" at the debugfs prompt. It's very interesting) Oh, well, thanks for the response anyways. -D
