Answers below
W dniu 28.06.2023 o 15:21, Kenneth Kripke pisze:
Hello,
We are in the process of implementing zEDC compression for DFHSM on our
test system to more or less shake out issues.
Questions have come up.
1. How to recover if there is a failure in deflation of a compressed
dataset. We have a mixture of z/14 and z/15 processors.
What kind of failure?
zEDC HW is redundant.
In case of recovery on machine without zEDC HW it is possible to
uncompress, but this is very CPU consuming.
2. For the z/15 processor, the footnote for the SMF 30 record indicates
that compression statistics are no longer recorded. How do you measure
compression? Is this also true for the SMF 14 and 15 records?
No idea.
3. Regarding deflation, is there a noticeable performance/delay ?
No. Sometimes one can observe small elapsed time profits.
Any information would be greatly appreciated.
My humble opinion: start using zEDC.
However consider your tape system - does it have compression enabled?
Do not compress the data twice.
Consider compression of your primary (DASD) datasets. In that case any
further compression is unreasonable.
--
Radoslaw Skorupka
Lodz, Poland
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