XRG is an open source system monitor for Mac OS X. XRG allows you to monitor CPU activity, memory usage, battery status, machine temperature, network activity, disk I/O, current weather, and stock market data. The goal of XRG is to be a functional system
He's backing up 2GB in ~20 seconds... The repo is standard git which is more efficient than anything else I know of. Backs up into $HOME/.git. Can rsync, etc that dir for efficient external backup.