Malarky. While I do use *CNTRLD, even after ending to restricted state,
please remember this; when you put a time limit on *CNTRLD after that time
expires it does an *IMMED.
When you do a PWRDWNSYS *CNTRLD DELAY(120) when you are in restricted
state it will stay there for 2 minutes, OR until you sign off your console
session. Therefore, using the DELAY is NOT the trick when you are in
restricted state - the trick is to sign off your console.
Now, as far as flushing cache, what kind of maintenance were they doing?
Replacing cache batteries? If so, RTM on doing so. To do this live
(which I usually do unless the battery is swollen and requires an outage)
the manual will talk you through the steps in SST to flush the cache and
make the battery ready for removal. For just one sample battery pack on
one card look at:
Now as far as powering down the system as a whole, on my HMC there's an
option, after I've powered off all the lpars, to power down the system
itself. I think there's an option there that says power it off so that
it's kosher to remove cache battery cards or not (or some such thing). I'd
love to show you a manual link but all I can see (from somewhere it that
above url) is "Select the desired power-off mode and click ok". And, I'm
not inclined right how to power off a whole system just to step one
through it. But given a little incentive for a couple of hours of after
hours work... ;-)