To check out the info on the filesystem to see what the settings are, when it was last mounted, etc , etc

tune2fs -l /dev/<devicefilename>

EXT2-fs warning: maximal mount count reached, running e2fsck is recommended.

df

to list all the partitions then run

fsck on all devices listed

If the ESX Host fails to boot.... (Sample of a corrupted root Filesystem /dev/sda3)

Download the inside boot CD http://www.inside-security.de/insert.html

Boot the system with the CD