Hi Kanagaraj, At last we identified the root cause is the px slaves. When we removed them from the init and bounced the instance, everything became normal. Thanks for the help. However, I will collect all the stuff that is provided by our forum members. Thanks to everyone who helped me for this. Thanks, Raj John Kanagaraj <john.kanagaraj@xxxxxxx> wrote: Raja, Were there any recent changes (on both Oracle and UNIX side)? High WIO could also be caused by heavy swapping (not just paging). Use sar -q to see the swap queue and sar -d to determine which disk (or LUN) is causing this issue... Did you have any memory errors that required a reboot and the Sa just pulled out some memory cards? Could be a lot of things, not necessarily Oracle. John Kanagaraj <>< DB Soft Inc Phone: 408-970-7002 (W) Co-Author: Oracle Database 10g Insider Solutions http://www.samspublishing.com/title/0672327910 ** The opinions and facts contained in this message are entirely mine and do not reflect those of my employer or customers ** --------------------------------- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of raja rao Sent: Monday, October 24, 2005 9:26 AM To: ganstadba@xxxxxxxxxxx Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: oracle is causing high WIO even after the startup restrict also the below is the WIO: $ sar -u 2 5 SunOS oracle 5.9 Generic_117171-02 sun4u 10/24/2005 12:09:30 %usr %sys %wio %idle 12:09:32 11 6 64 19 12:09:34 12 7 66 16 12:09:36 4 1 90 6 12:09:38 0 0 94 5 12:09:40 0 0 90 10 $ --------------------------------- Yahoo! FareChase - Search multiple travel sites in one click.