If you are seeing error messages in syslog, your file system becomes readonly or if you just suspect a problem with the filesystem, you can check the filesystem. Unfortunately this should to be done when the filesystem is not mounted. To start a filesystem check run the following command:
fsck -C0 /dev/md2
The -C0 displays a progress bar. For every error found you will be asked whether it should be repaired or not. If all errors should be corrected automatically, the -y option can be used:
fsck -C0 -y /dev/md2
To be on the very safe side, the fsck can be run with the explicit file system type instead of autodection, e.g.:
fsck.ext3 /dev/md2 fsck.ext2 /dev/md2 ...
Note: If fsck stops with "exited signal 11", it may help to use the fsck version of the installed system. To do that, the root partition must be mounted and all files required for fsck have to be copied into a directory of the rescue system. Do not forget to unmount the partition with umount before running the filesystem check!
The fsck versions for the different filesystems must be called explicitly inside the new directory. Otherwise the version of the rescue system will be run.
./fsck.ext3 /dev/md2
