A former co-worker had a problem last week during a scheduled maintenance window and the analysis afterward led a consultant to say this in his root cause analysis report:
"Anytime you are doing any kind of disk work on a system you always want to power the system down controlled. Ending the system "controlled" flushes the disk cache from memory to disk, "immediate" does not do this. I cringe when I see customers using *IMMED. 99% of the time the system will come back up without issue, but that other 1% results in the type of issue reported here. They took the time to end all of the subsystems to a restricted state before issuing the PWRDWNSYS, which is the right thing to do, but then powered down immediately. It's a common misconception that ending the system controlled takes significantly longer to end. Once the system is in a restricted state, it takes only seconds longer to end the system "controlled" versus "immediate". The trick to using *CNTRLD is to make sure you change the delay time to something like 5 (for 5 seconds) rather than the default of 3600, otherwise you'll be waiting an hour before the system starts powering down."
I have to say in 27 years of administering the platform in all its flavors I've never done a PWRDWNSYS *CNTRLD and I have yet to have any problems caused by that. Thoughts anyone??
Paul Fenstermacher | Sys/NW Admin,Sr | Corporate Systems - POWER Systems Administration | Jack Henry & Associates, Inc.(r)
663 West Highway 60 | Monett, MO 65708 | Ph. 417.235.6652 | x177389 | pfenstermacher@xxxxxxxxxxxxx<mailto:pfenstermacher@xxxxxxxxxxxxx>
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