Hi Yong, Yes I have used those commands http://yong321.freeshell.org/osnotes/FreqCmds.txt before they were helpful, but I ended thinking if Tanel got his memory accounting tool (based on pmap) on Linux that would be sweet.. Also thanks for sharing aotop, I know I've came across this website before but didn't know it can do disk activity per process. but, do I still need to patch the kernel? It also got a nice case study on the extras https://docs.google.com/viewer?url=http://www.atoptool.nl/download/case_leakage.pdf And also, if you're on RHEL5 collectl ( http://collectl.sourceforge.net/Process.html) got this top like switch collectl --top rkb that can sort per process KB read/write.. which again I wish could be installed on < RHEL5 -- Karl Arao karlarao.wordpress.com karlarao.tiddlyspot.com