The /var partition randomly mounts read-only, when I reboot it mounts as rw again.
OS: CentOS 5.4
partition: /var, size: 80G
the /var is for web logs and MySQL data file.
Possibilities are:
First thing you must check whether the HDD IO and it's functionality, performance. In order check the IO please take a look into this question.
iostat -x -d
(will do the trick)
If you have filesystem error, boot your server into single user mode then run,
fsck -a -f
this will resolve your filesystem issue.
Likely you have a hardware problem with your disk, or corruption from some other reason. When a file system errors is detected, the filesystem is usually remounted read only.