Also set the Java Heap as low as possible relative what the appl needs. A too big heap just cause problems with cache and longer time for gc.
Cordialement / Vriendelijke Groeten / Best Regards / Med Vänliga Hälsningar Tore Agblad Volvo Information Technology Infrastructure Mainframe Design & Development SE-405 08, Gothenburg Sweden E-mail: [email protected] http://www.volvo.com/volvoit/global/en-gb/ ________________________________________ From: Linux on 390 Port [[email protected]] On Behalf Of Rob van der Heij [[email protected]] Sent: Wednesday, February 17, 2010 16:19 To: [email protected] Subject: Re: What about these VMSTAT 5 numbers? On Wed, Feb 17, 2010 at 2:49 PM, Mrohs, Ray <[email protected]> wrote: > Hi, > We are running SLES10 and WebSphere on 1 IFL and 2G storage. These > bursts of activity seem to happen every few hours. > Is occasional swapping in the thousands too high if its going to VDISK? > What can cause the high 'wa' values? Our info is limited since this is a > test partition with no VM performance monitoring (yet). > Thanks for any insight! The "wa" column is % of time waiting for I/O. Your vmstat data shows swapping, so my guess is that you're swapping to real disk and the process is in I/O wait for the swap-in. So the virtual machine is too small for this workload. Since this spike happens frequently, it could be the JVM Garbage Collection going through the entire JVM heap and force all pages to be swapped in. Your page cache is rather large for a WAS workload, might be a good thing to lower the swappiness. Increasing the virtual machine size or adding VDISK for swap would help, but can't say whether that fits without seeing z/VM data. Did I already mention Performance Monitor? Oh, you did ;-) -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
