Browse Tag: rescue

Recover an ext3 journal

Symptom:
dmesg scrolling with “journal aborted”, filesystem in read-only

Give this a go (may need a rescue environment):
[code lang=”bash”]tune2fs -f O ^has_journal /dev/sda1
tune2fs -j /dev/sda1[/code]

Recover ext3 filesystem with missing superblock

Symptom:
[code lang=”bash”]mount: wrong fs type, bad option, bad superblock on /dev/sda1, or too many mounted filesystems[/code]

Usually, this is code for “you’re fucked”. Here’s something you can try, however:

List the proposed superblocks (filesystem must be unmounted):
[code lang=”bash”]mke2fs -n /dev/sda1[/code]

fsck the filesystem using a backup superblock (caution, should try with -n switch to fsck first):
[code lang=”bash”]fsck -b 24577 /dev/sda1[/code]

If it fails, scan for the superblocks and use one of those:
[code lang=”bash”]dumpe2fs /dev/sda1 |grep super[/code]

Then again, if using a backup superblock doesn’t work, you’re probably fucked, as originally thought.

Custom drivers in the RHEL rescue environment

If one or more of devices has a custom driver not present in the rescue environment, put them on an external media source such as a thumb drive, floppy, CD, etc. Once at the rescue environment prompt, start it with

[code lang=”bash”]linux dd[/code]

Follow the prompts for success.