by System performance analytics seems to be a frequent question on forums and mailing lists. Finding out why something is slow is generally nontrivial as there are many factors to consider. I have found the sysstat package to be an invaluable tool when looking at system performance. Specifically the command sar gives a wealth of information.
Read the full post [http://www.cmdln.org/2008/04/13/analyzing-linux-system-performance-and-finding-bottle-necks/|Analyzing linux system performance and finding bottle necks]