ext3 (Superblock) damage while partition extend
I lost the ext3 File system after resizing the Partition on an md raid device. The whole story:
I added an SSD and freshly installed Centos 6. The Raid devices for the former / and swap had to be deleted and the Data Partition should receive the entier disc capacity. I started with two hard disks, having three partitions type fd and three raid1 devices. Code:
/dev/sdb1 50G Linux raid auto Code:
/dev/sdc1 50G Linux raid auto Code:
md125:active raid1 sdc1[1] sdb1[2] [UU] ext3 (previously mounted on /) Code:
mdadm /dev/md126 --fail /dev/sdb2 --remove /dev/sdb2 Code:
/dev/sdb1 320G Linux raid auto Code:
mdadm -a /dev/md126 /dev/sdb1 Code:
mdadm --grow /dev/md126 -z max Next step was to extend the partition /dev/md126p1. Using fdsik /dev/md126 i deleted the partition (form 1 to 32028) and created an new one (form 1 to last). From that moment on, the ext3 is not detected as ext3 anymore and unusable even with -t ext3. It always says "wrong fs type, bad option, bad superblock" I tried to use backup superblocks displayed by mke2fs -n via fsck as well as via mount -o sb=1234 - nothing. Can someone help me finding the Data? thanks, datashredder |
meanwhile is set up a perl script
Code:
foreach (30000..30000000){ Any idea, please? datashredder |
Normal response when screwing with partitions - restore from the backup you took before you started screwing around.
No, I'm not being flippant. That said, it looks like what you did is sane - I'd blame fdisk. Recent versions align partitions differently for compatibility with the newer 4k sector drives - if the old alignment was to cylinder 1 (as in sector 63), the filesystem won't align to the start of the new partition. So your filesystem would be ok, but you won't be able to find it. "fdisk -l" should tell you. (I didn't reply earlier as I didn't want to pull you off the "0 reply" list). |
Thanks for your reply, syg00. Ok - i found in the web, that fdisk since v. 2.17.1 (i used 2.17.2) aligns the partition begin to a sector divisible by 1024, if the DOS compatibility mode is disabled. But i can see the partition beginning at sector 1. Are the more new behaviours? I think, i give an old recue disk a try to recreate the partition.
thanks datashredder |
The only partitioning tool I know that will do exactly what you tell it to do is sfdisk when run with the "--force" option, but you will have to put up with a non-interactive user interface that sometimes doesn't seem to have been intended for humans.
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Thank you guys,
after using an old fdisk, that didnīt help, i decided to restore the backup. It might be very interesting to find out, what happened, but i have neither enough disks nor sufficient time. datashredder |
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