Peter, Thanks, that's not a issue of rasort, should be the cause of the limitation of my box, I tried to run rasort with -R for the files lesser than 300MB and it goes fine and only after it exceeds certain big file size then it goes dumping. I'm now recompiling my kernel to see how things go. Thanks for the tip. -- Best Regards, CS Lee<geek00L[at]gmail.com>