Looking for a good server log analytics app

Can anyone recommend a good analytics app that they’ve had good luck running on a dreamhost VPS?

I’m trying to pinpoint why I’m getting spikes in our memory usage so I’d like to throw our logs into something that will help me analyze the usage data.

Not looking for visitors and where they went Google Analytics type stuff, but rather memory, CPU, bandwidth usage, and some simple IP use rankings.

Thanks for any recommendations!