Originally posted by: SystemAdmin

I tried to tune the maxperm and minperm. From IBM lib, I can decide what value for the maxperm, but I do not knw what minperm whould be. From some of VMM tune guide mentions to use the following as a guide line
minperm = ((num of page frame) -1024 ) * 0.2
However I have no idea how to find our the num of page frame of my system (AIX 5.3L)
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Originally posted by: nagger

Which document did you find this in?
It seems like a complex way of trying to decide what to set this tuning variable too and I think pointless as this is about the number for the default setting i.e. minperm=20% of memory and maxperm=80%.

I think this is the number you want:
vmo -L | grep memory_frames

I recommend only changing minperm and maxperm, if you know what you are doing and you actually have a problem.
The typical reason is when your database is NOT using the filesystem cache (i.e. using raw devices or direct or concurrent I/O) and so you want to keep the SGA or buffer cache in memory and so lower the filesystem cache. I then recommend minperm=55 and maxperm=20% but your milage may vary depending on the database cache sizes you intend to use.

Hope this helps, N

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Originally posted by: SystemAdmin

In Oracle Database Administrator Reference 10g Release 2 for Unix-base (B15658-05)
it use
minperm (in pages) = ((number of page frames)-1024) * 0.2
In the IBM document:
http://www.unet.univie.ac.at/aix/aixbman/prftungd/vmmpage.htm
minperm (in pages) = ((number of memory frames) - 1024) * .2

None mentioned how to define the page frame or memory frame.
and in my AIX 5.3L system for

1. vmo -L | grep memory_frames

memory_frames
memory_frames
memory_frames 948K 948K 4KB pages S
memory_frames
so memory_frames is (page frame) 948K (948000)?
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Originally posted by: SystemAdmin

That "IBM Document" is from 1996 and applies to AIX Versions 3.2 and 4. You are running AIX Version 5.3, in which case I would be skeptical of the applicability of anything in that document. You can find newer information on how to properly tune AIX 5.3.

The follwing link to a page from the IBM pSeries and AIX Information Center has information on how minperm/maxperm are used to control the "ratio of page frames used for files versus those used for computational (working or program text) segments":
http://publib.boulder.ibm.com/infocenter/pseries/v5r3/topic/com.ibm.aix.prftungd/doc/prftungd/values_minperm_maxperm_param.htm

If you look at the above link, you will notice that minperm/maxperm should be specified as a percentage not as a number of pages. You'll also notice that the codevmstat -v[/code] command will tell you the number of pages in memory.

Additionally, if you look at the document you linked to, it states that the equations given are used for calculating the default values for minperm/maxperm.
"The default values are calculated by the following algorithm:

minperm (in pages) = ((number of memory frames) - 1024) * .2
maxperm (in pages) = ((number of memory frames) - 1024) * .8"

Given this I do not know why you are trying to calculate minperm/maxperm with these equations. Are you trying to find out what the default values should be, or what you should set them to in order to improve performance? If you are tying to determine new values for minperm/maxperm in order to improve performance, then using these equations will not help you.

You may want to start out by perusing the 'Performance Management and Tuning' Section of the IBM pSeries and AIX Information Center:
http://publib.boulder.ibm.com/infocenter/pseries/v5r3/topic/com.ibm.aix.doc/doc/base/performance.htm

You may also want to check out the IBM Redbooks that pertain to AIX:
http://www.redbooks.ibm.com/cgi-bin/searchsite.cgi?query=aix&qapromo-s0sd-b0sd-l0rb-d0sdrb-n015-o0aix-g0usen
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