On Monday, 11/04/2013 at 09:00 EST, Aria Bamdad <[email protected]> wrote: > That's what I pointed out in my last reply. You cannot change the time on a > running VM system. Your only option is to re IPL VM.
When you change the time at IPL, you actually change the TOD clock in the LPAR. CP uses the the timezone he thinks he's in in order to calculate a new UTC value for the TOD. If the TIMEZONE_BOUNDARY statements are wrong, so will be the UTC calculation. And all guests get that same TOD. As you say, if you do change the TOD clock at IPL, the only way to fix it is to re-IPL (with STP enabled in hw and SYSTEM CONFIG) or deactivate/reactivate the LPAR (without STP). FEATURES ENABLE AUTO_IPL WARM (for normal IPL) AUTO_IPL_AFTER_RESTART WARM (or FORCE, your choice) AUTO_IPL_AFTER_SHUTDOWN_REIPL WARM will ensure that your operations folks do not get the opportunity to screw around with Time. As we all know, humans inevitably tear a hole in space-time and the Universe is destroyed and arises anew. Happened before; will happen again. Adding the STP feature to the machine to ensure this doesn't happen on your watch (no pun intended) seems worthwhile. Please note that CMS can give you perplexing results as it's a bit schizophrenic when it comes to time. Sometimes CMS gets local time from DIAG 0x270 and in other cases from the TOD. (For a bit of scary fun, read DMSSTM ASSEMBLE, the source for the CMS simulation of the MVS TIME, STIMER, STIMERM, and TTIMER macros.) Alan Altmark Senior Managing z/VM and Linux Consultant IBM System Lab Services and Training ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 [email protected] IBM Endicott ---------------------------------------------------------------------- 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 more information on Linux on System z, visit http://wiki.linuxvm.org/
