Jesse 1 Robinson wrote:
I sympathize with IBM's predicament in reading the future maintenance tea
leaves. The 'fix rate' for a product might be subject to guesstimation from
past experience. But the effects of future enhancements like SPEs and customer
requirements are a bundle of uncertainties wrapped in unknowns. The change from
six month to two year release cycles further clouded space predictions.
I think customers are best off expecting data set expansions. A few like
LINKLIB and LPALIB can be deliberately oversized as likely candidates for
increase in a variety of components. But the migratable sysres volume is
limited to whatever size installation has settled on. Secondary extents, in my
view, allow for unpredictable expansion with acceptable risk.
While we have long provided some cushion in the initial numbers and in
ServerPac (and before it, CBIPO and even IPO) allocations, we have
really left further guessing to you. I expect that we will err on the
side of more free space pretty soon to help alleviate out of space
problems in this new(er) era of larger system software volumes,
particularly because system software is such a small fraction of the
disk space requirements for nearly any shop out there.
In the long term I think everyone is better off moving all their
software volumes to -54s, doubling or even tripling all the primary
space allocations, and using thin provisioning to manage space at the
volume level rather than the data set level. It will be approximately
true that only occupied space takes up actual disk real estate when you
do that. (I say "approximately" because there is an increment size, and
on the average every data set will have an extra half-increment.)
System software data set level space management and x37 abends during
APPLY and ACCEPT processing will, I would hope, become a fading memory
in a few years. Unlike some other memories, nobody will miss the "good
old days." This will be more like the stories about how much more
complicated life used to be when you had to walk to school. It was
always uphill both ways and it was always cold and snowing. At least,
that's what people used to tell their kids who rode those cushy heated
(FSVO "heated," at least in Maine) buses, right?
--
John Eells
IBM Poughkeepsie
ee...@us.ibm.com
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