I'm curious. If you have a sysplex with say 2 separate CPUs, can you set
that up so that if one CPU crashes, that the other can take over
immediately? I seem to remember reading about that long ago, where you can
have the same CICSs and DB2 regions all up on both boxes, but all
transactions are routed to one box or the other. Then, if one CPU would
die, the other could take over immediately, with no wait. Is that the way
it works, or am I not remembering correctly? If that is the way it works,
that would mean a lot to that other thread on EMC and PAVs.
I have experience at 2 of my contract jobs in a sysplex environment. The
first job actually had 2 z/900s in the same room. My last job was 2 Lpars
in a sysplex on a z/800. Both were done to save on software costs. As a
matter of fact, on the 1st job, after the holiday season ended they hard
capped both CPUs to I think 85% of capacity, which I'm sure saved them a lot
of money. They ran CICS on the 5 engine box, and DB2 batch jobs on the 3
engine box. I don't think anyone complained when the cap was put on. I
think the batch spent a lot more time waiting in the input que, but overall
CICS response time wasn't affected as that processor rarely ran at 100%, and
when it did the batch just took longer.
I know at my last job with the single z/800, they were told that the sysplex
overhead was 10-20%. To me, that is a LOT of overhead, but it did enable
them to save money on software. I think they got rid of the system that
needed CICS, so I think by now they probably eliminated the sysplex and get
a much lower overall cost. I know they also got a z10, so software costs
also were reduced by the z10.
Eric Bielefeld
Sr. Systems Programmer
Milwaukee, Wisconsin
414-475-7434
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