I agree that in the past the Linux activity requirements For I/O are different then zVM. If your Linux Guest becoming unresponsive, review; CMD: Q QUICKDSP userid CMD: CP QUERY SRM STORBUF CMD: CP SET SRM STORBUF xxx xxx xxx' (may really help) CMD: QUERY ALLOC PAGE CMD: Management may buy you more z memory! Regards -----Original Message----- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Robert J Brenneman Sent: Wednesday, January 28, 2009 9:57 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Linux Guest 'swapping'
Just a guess till the experts chime in: Linux disk I/O activity requires more CPU time than traditional Z Operating systems - so when one guest starts driving 5000 I/O ops per second to the swap device ( FBA mode vdisk in my case ) that in itself consumes a big chunk of CPU. Then there's the additional time spent in the linux kernel itself deciding what needs to go out to swap and what needs to come back in. let me re-emphasize this is a guess - I'd like to know the answer to this too. -- Jay Brenneman -----Original Message----- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Steve Mitchell Sent: Wednesday, January 28, 2009 9:01 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Linux Guest 'swapping' Last Thur afternoon my IFL's went to nearly 100% for extended periods. One linux guest running three WebSphere app servers was the culprit. After determining the cause to be the JVM of one the servers causing linux to swap the JVM, we increased the size and restarted server. Things are find again. Monday AM all day same situation different server CPU at or near 100% (for 2 IFL's), WebSphere Admins research and determine the JVM needs increased in another server and the guest needs more Memory. I give the guest 700M to a total size of 4G. Log machine off and back on. Since then this guest runs in the 40-50% range vs the 90-80%. What I am unable to understand is why did one linux guest 'swapping' cause the IFL to be totally consumed? NOTE: VM worked great no other guests were effectted to the point user's complained. -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean.
