iostat -x « domas mituzas: vaporware, inc.
http://dammit.lt/2009/03/11/iostat/
Measuring & Optimizing I/O Performance - igvita.com
http://www.igvita.com/2009/06/23/measuring-optimizing-io-performance/

Typically excellent post from Ilya Grigorik.

An indepth look at disk i/o throughut, measurement and performance monitoring within Linux

Good, quick introduction to vmstat, iostat, and top for checking Linux performance stats.

what ought to be common knowledge about vmstat, iostat, and top

basics.