Almost every AIX paper on memory settings for Oracle has a line that reads:
"Do not over commit real memory"
Which is somehow trivial; I'd say it applies to any OS...
Anyhow, was wondering is someone in forum has done the math as to proactively determine which usage % of real memory (Physical RAM)
is prone to "over committing real memory" and eventually PGA or, even worse, SGA paging...
i.e. what % to set SGA + PGA so as to make sure memory will not be over committed?
So, for example, given the following scenario:
AIX 6
64Gb RAM
Oracle 11g R2
ASMM
Direct I/O (JFS2 / CIO)
Would 80-20 rule apply here? i.e: SGA + PGA <= 80% RAM?
i.e: Any rule of thumb on how much memory is needed by AIX to keep paging activity at the minimum
Another question I have is related to page space setting, 11G R2 install doc reads:
On AIX systems, with 1 GB or more of memory, Oracle recommends that you set the paging
space to an initial setting of half the size of RAM plus 4 GB, with an upper limit of 32 GB.
RAM Swap Space
--------------------- -----------------------------
Between 1 GB and 2 GB 1.5 times the size of the RAM
Between 2 GB and 16 GB Equal to the size of the RAM
More than 16 GB 16 GB
So for configuration above (64Gb RAM), is Oracle's recommendation 32 or 16Gb?
thanks