W dniu 26.03.2021 o 22:00, Crawford, Robert C. pisze:
According to the documentation, after z/OS 2.3 the LFAREA parameter no longer
reserves real memory for large frames at IPL. Instead, it's a limit on the
number of fixed 1M frames.
Since it's now a limit is there any harm in leaving LFAREA too high as long as
you keep an eye on large fixed frame usage and paging?
I'm asking because we have some LPAR's with wildly underused LFAREA's and few
opportunities to exploit them. The lazy systems programmer in me would rather
leave LFAREA alone rather than try to pick a target value that needs to be
closely managed.
My experience: leave LFAREA "too high" and don't worry.
My bad experience: when you IPL the system on LPAR with much lower
memory and us use DB2 with huge bufferpools you will have problems.
Solution: DB2 v11 - bufferpools can be changed using a job, before DB2
is started. DB2 v12 - it is more complex, of course you can change
bufferpools in advance (which is not always possible due to performance
affect).
--
Radoslaw Skorupka
(looking for new job)
Lodz, Poland
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