Hope someone out there in CMIS land can help me.

We had an issue this morning where EPortal grounded to a halt.
I checked on our virtual server which was running at 100% cpu.

When it was rebooted - Eportal still was not running ok.
Don't know why but after a second go all was brill.

Does anyone have any ideas what might have have happened, and secondly are there any tools out there that can help diagnose these performance problems.