Check rw-mounted linux filesystem without reboot
25th June 2007
If you happen to need to check your linux filesystem, which is mounted read-write, and for some reason you do not want to reboot, then the simple sequence of commands listed below should help you. Note, that the commands provided put you into single-user mode, which kills web-server and mysql daemon.
So, running e2fsck on a live (mounted) filesystem isn’t recommended – and f2sck asks if you really want to check the rw-mounted FS (be sure to answer ‘n’o). If the FS you want to check is root (/), you cannot also re-mount it read-only – unless first you go to single-user mode:
init 1
Now you can re-mount your FS read-only:
mount -o ro,remount /dev/cobd0
(/dev/cobd0 is my device, replace it for your device when repeating step-by-step).
Filesystem is now read-only, and it’s safe to run e2fsck:
e2fsck -D -C 0 -f -t -v /dev/cobd0
e2fsck options are optional:
-D: optimize directory structure
-C 0: show progress
-f: force check (use if you get “volume is clean” with no check)
-t: e2fsck timing statistics
-v: verbose mode
Finally, return to your previous user mode:
init 3
