Mysql showing some high spikes [closed]
/var/lib is really big, and mysqls data directory resides there by default in many distributions. Can you do a du -sh of /var/lib, and in case mysql is there do a du -sh of that directory too.
You might want to try out mysqltuner.pl, to get an overview of how much data and indexes you have, how the buffers and caches are trimmed, your amount of queries and slow queries (etc etc).