Check for co-incident processing. E.g. SMF and RMF (both) synchronized on the hour. This has been know to cause spikes when everyone is trying to do everything all at the same time.
DDCONS=YES for a long running system task (e.g. DFHSM) that was terminated. Perhaps a "high priority" batch job looped and then timed out. RMF Mon III may have some additional clues. HTH, <snip> > We just experienced a 4 minute 'outage' on our z/OS system. (single image > z/OS 1.9 system). > > By 'outage', I mean we could not communicate with MVS through TSO or the > z/OS consoles. There is a 4 minute gap in SYSLOG. The same for CICS, IMS > and DB2 logs. > > There were no system dumps or other indicators. > > We reviewed SYSLOG for the 15 minutes that preceeded the 'outage' and did > not find anything. TMONMVS had a 4 minute gap in the collector during > the 'outage'. > > Any suggestions how we can determine what happened?-- </snip> Check for co-incident processing. E.g. SMF and RMF (both) synchronized on the hour. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html