Originally posted by: fplatel

Hi,

I would like to collect point of view of admins dealing with performance tuning regarding minfree/maxfree settings.

My understanding about these two tunables is that they allow to keep free a certain amount of memory pages so that they are immediately available at any time unless the minfree pages have been consumed and the page replacement didn't free pages quickly enough.

So, on some of our customers servers having somewhat big memory size (96GB and more), I have set minfree/maxfree to high values like 16384/16640 or 32768/33280. With such high values, I expect that when the processes on the server have to allocate some memory, I have around up to 64MB (or 128MB) already available for being able to immediately honour the memory allocation request instead of having the processes blocked until the needed pages have been freed, thus I expect to have better response times in applications.

I would like to know if some of you can see any drawback of this high values of minfree/maxfree : in my case, our servers are usually sized so that we should not see much memory overcommit and we set lru_file_repage to 0 in order to give priority to computational memory pages.

So the only drawback I see from my point of view is that in case the memory is getting full of computational pages, I just will have minfree pages not permanently available in real memory that will have to be stored in paging space instead.

Any other opinion ???

Thanks in advance for sharing experience.
Fabrice
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Originally posted by: hdkutz

Hello,
this:
https://www.ibm.com/developerworks/aix/library/au-aixoptimization-memtun1/
helped me a lot to understand AIX Memory Usage.

Cheers,
ku
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