David, What kind of SHARE statements do you have in the Linux servers' directory entries. That's what determines how much of the available CPU resource the users get. Marty ____________________ Martin Zimelis Principal maz/Consultancy
_____ From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Dean, David (I/S) Sent: Thursday, November 12, 2009 1:17 PM To: IBMVM@LISTSERV.UARK.EDU Subject: zVM CPU allocation OK, this is for all you guys that understand the magic tunnel in which CPU processing (usage) flows from an IFL to a zLinux server. We have a z10 running zVM 5.4 in a dedicated LPAR with 3 dedicated IFL's. We have approximately 30 zLinux servers. Using IBM PerfKit, I list all of the individual USER / zLinux CPU usages, each of which generally run in the 1 to 5 % range. These servers do of course peak higher but on average they are pretty low. We then take a look at the 3 IFL's and see usage of maybe 5% on each. Now, let's say we have a USER / server or two or three go berserk and peak CPU at 99 % for an extended period of time. We then look at the IFL CPU usages and all three have climbed to maybe 10 to 15% each. How did the CPU get allocated? Is it always spread evenly across the IFL's, is that a setting? Why, if there were 3 USER / servers running at 99%, was more CPU not allocated from the 3 IFL's? Why did the IFL's decide to allocate X amount and go no further. In the USER DIRECTORY I allocate storage but not CPU. David M. Dean Information Systems BlueCross BlueShield Tennnessee ----------------------------------------------------- Please see the following link for the BlueCross BlueShield of Tennessee E-mail disclaimer: http://www.bcbst.com/email_disclaimer.shtm