No problem with asking back, Ptrik!!
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As far as I understand, shared pools are about memory or main storage, and paging activity levels. Subsystems are about grouping jobs with appropriate time slices and/or priorities, and enable routing of "incoming work" to these subsystems. Right?
I guess I don't see that as a firm divide, I see it all as cut from the
same cloth. Pool definitions are a part of the SBSD. These can be set up
to use a shared pool, whether things like we had a long time ago like
*INTERACT. Or they can be set up as private pools.
Fixed pools are used only by the subsystem whose description specified
them. Shared pools are separate from subsystem descriptions and can be
used by several subsystems.
Managing performance is a combination of the factors you list. Paging is
not activity levels - maybe you left out a comma - and paging is more
easily set for shared pools, as I recall from many years ago.
I'll just throw in a model I heard from an IBM instructor when I first
worked with this - I was at Help Systems and was a tech support person,
mostly responsible for the AutoTune product, which is a dynamic
performance tuning application. IBM took some of the took away some of
the need for Autotune when they gave us setting like we have today.
So the picture - say you have 50 people who want to go swimming - and
your swimming pool has room for only 30 - that is your activity level
for that pool. There is also a max active for the entire water sport
recreational complex.
Time slices could be how long a person can stay in the pool before the
lifeguard checks to see if anyone else want to get in. If the number of
people in the pool is less than the activity level (30), then someone
else can jump in,
If there are 30 swimmers, then at a certain time, if someone else wants
in, the someone has to get out. Smaller pools might cause this thrashing.
Anyhow, enough silliness - it's been far too long since I worked in this
area, anyhow.
Best to you
Vern
Please don't get me wrong, I don't want to offend in any way. I just have a (maybe sometimes nasty) habit to ask back when I feel that an answer maybe has been given because of because-we've-done-it-that-way-ever-since. :-)
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