Hi all, I'm trying to fix a 7.5Tb ext3 filesystem using e2fsck on a x86_64 machine with plenty of memory ram. The filesystem is corrupted, but I can mount it. Before starting the filesystem check, I did a LVM snapshot to be able to start it again from the same point in case of error. After 12 hours checking the filesystem, I got this error message: Pass 1: Memory used: 268k/18014398508105072k (59k/210k), time: 65673.66/1550.92/1371.06 Pass 1: I/O read: 253456MB, write: 23885MB, rate: 4.22MB/s Restarting e2fsck from the beginning... e2fsck: Superblock invalid, trying backup blocks... e2fsck: Bad magic number in super-block while trying to open /dev/storage/cabina_snapshot Once I saw this message, my first thought was that e2fsck didn't manage to fix the filesystem and it corrupted the superblock. To be sure I dumped the entire block and compared it against the original superblock. Doing that I realized that the entire superblock only contained zeros. Any ideas of what can I do? Thanks you very much. -- Albert Sellar?s GPG id: 0x13053FFE http://www.wekk.net whats at jabber.org Linux User: 324456 -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 198 bytes Desc: Aix? ?s una part d'un missatge signada digitalment URL: <http://listman.redhat.com/archives/ext3-users/attachments/20100221/e78c14ea/attachment.sig>
The system is using the backup superblock -- which sounds reasonable, under the circumstances, and should result in a half-decent recovery. A couple of questions: Was the superblock zero to begin with, or did it become zero during the FSCK? In either case, I'm worried about the zero data having been written. This is obviously worth further investigation. Did the system abort the FSCK after this error? or did you stop it? did you try explicitly using one of the backup superblocks? a list of backup superblocks can be found by using -n on mkfs check the -b option on fsck.ext2 for more details on the backup superblock defaults. 2010/2/21 Albert Sellar?s <whats at wekk.net>> Hi all, > > I'm trying to fix a 7.5Tb ext3 filesystem using e2fsck on a x86_64 > machine with plenty of memory ram. The filesystem is corrupted, but I > can mount it.is > > Before starting the filesystem check, I did a LVM snapshot to be able to > start it again from the same point in case of error. > > After 12 hours checking the filesystem, I got this error message: > > Pass 1: Memory used: 268k/18014398508105072k (59k/210k), time: > 65673.66/1550.92/1371.06 > Pass 1: I/O read: 253456MB, write: 23885MB, rate: 4.22MB/s > Restarting e2fsck from the beginning... > e2fsck: Superblock invalid, trying backup blocks... > e2fsck: Bad magic number in super-block while trying to > open /dev/storage/cabina_snapshot > > Once I saw this message, my first thought was that e2fsck didn't manage > to fix the filesystem and it corrupted the superblock. To be sure I > dumped the entire block and compared it against the original superblock. > Doing that I realized that the entire superblock only contained zeros. > > Any ideas of what can I do? > >-- Stephen Samuel http://www.bcgreen.com Software, like love, 778-861-7641 grows when you give it away -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://listman.redhat.com/archives/ext3-users/attachments/20100221/8f29dc7b/attachment.htm>
On 2/21/2010 3:51 AM, Albert Sellar?s wrote:> Hi all, > > I'm trying to fix a 7.5Tb ext3 filesystem using e2fsck on a x86_64 > machine with plenty of memory ram. The filesystem is corrupted, but I > can mount it.What partition table format are you using? I sure hope it's not msdos. If it is your problem might be caused by this. I once had similar problems. I was able to replace the msdos table with a GPT table, and then use the gparted 'rescue' command to recover without loosing a single bit of data. Cordially, -- Jon Forrest Research Computing Support College of Chemistry 173 Tan Hall University of California Berkeley Berkeley, CA 94720-1460 510-643-1032 jlforrest at berkeley.edu
Albert Sellar?s wrote:> Hi all, > > I'm trying to fix a 7.5Tb ext3 filesystem using e2fsck on a x86_64 > machine with plenty of memory ram. The filesystem is corrupted, but I > can mount it. > > Before starting the filesystem check, I did a LVM snapshot to be able to > start it again from the same point in case of error. > > After 12 hours checking the filesystem, I got this error message: > > Pass 1: Memory used: 268k/18014398508105072k (59k/210k), time: > 65673.66/1550.92/1371.06 > Pass 1: I/O read: 253456MB, write: 23885MB, rate: 4.22MB/s > Restarting e2fsck from the beginning... > e2fsck: Superblock invalid, trying backup blocks... > e2fsck: Bad magic number in super-block while trying to > open /dev/storage/cabina_snapshot > > Once I saw this message, my first thought was that e2fsck didn't manage > to fix the filesystem and it corrupted the superblock. To be sure I > dumped the entire block and compared it against the original superblock. > Doing that I realized that the entire superblock only contained zeros. > > Any ideas of what can I do?What is the blocksize of your filesystem? RHEL4 should be safe for 2^31 blocks, which -should- get you to 8T at 4k blocks. dumpe2fs -h info would show us (long as you have an intact superblock somewehre...) But if you were beyond 2^31 blocks I imagine you'd have hit troubles early on. -Eric