LPAR Frozen with HIGH CPU

[William Boyer]

Last Friday we had a situation where our production LPAR – running z/VM 5.1 with two z/OS guests – hung or rather ran away with the CPUs.  From the test LPAR, we only have two LPARs, I could see using the Performance Toolkit that the production LPAR was running at 97% + of all three CPU’s. The test LPAR, which only has one CPU assigned to it was using the remaining percentage.  When I tried to logon to the production z/VM, I got no response until I got a message the External Security Manager was unavailable.  We run RACF/VM on the system.  Luckily, I had a userid logged on via the ICC however; when I typed a command in I got an immediate NOT ACCEPTED.  I then tried a PA1 to get a CP READ that did work although it was slow.  I was then able to issue an IND commands but could not really tell which processes were consuming the CPUs.  I say processes plural because the only userid with more then one CPU defined is the one z/OS and it only has two CPUs defined.  The LPAR has 3 CPUs total assigned to it.  I tried to force some of the users I saw in the CPU queues but they just hung with a LOGOFF/FORCE pending.   We re-activated the LPAR and everything came up normally.  There was not trace of what happened in dumps or anomalies in any logs either z/VM or z/OS.  Anyone every have something like this occur?  If it occurs again does anyone have some ideas of what to try to figure out what is happening?   Thanks.   William L. Boyer Senior Systems Programmer   ViPSÒ, an Emdeon Company One West Pennsylvania Avenue Baltimore, MD  21204 Office:  410.832.8300 ext. 8419 Fax:     410.832.8327   This message is confidential, intended only for the named recipient(s) and may contain information that is privileged or exempt from disclosure under applicable law.  If you are not the intended recipient(s), you are notified that the dissemination, distribution, or copying of this message is strictly prohibited.  If you receive this message in error or are not the named recipient(s), please notify the sender at either the fax address or telephone number above and delete this message.  Thank you.