Disk i/o and load

Hello recently one of my sites goes very well.My server goes to load 6 and i want to reduce it.So my first thought is that i will keep my cached documents to ram,but to do that first i must identify that the load is caused by them.So how to identify if hd is the reason for high load?
I think that cached documents are the reason cause are more than 300.000 cached documents at hds 8gb aprox.

 

I'd install munin - the graphs should help you to find out if the disk is the problem.
http://www.howtoforge.com/server_monitoring_with_munin_monit_debian_etch

 

Falko,

Can you able to provide this for CentOS and RHEL that would be great.

 

Here you go: http://www.howtoforge.com/server-monitoring-with-munin-and-monit-on-centos-5.2