About the Filesystemcache on AIX

As for the Filesystemcacheon Aix , the following books have been discussed:

Oracle tuning Diary for eel with: The story of a gold DBA . pdf

See page 165 :

This filesystemcache,Nmon after entering, after knocking m can see. The following is an example:

Notice the upper right corner of the display:

filesystemcache(numperm) 66.8%

Process 28.3%

System 4.8%

Free 0.2% The sum of the three is approximately equal to 100%

That is, the footprint of all physical memory is shown here.

Special attention:

Filesystemcache ( Numperm ) actually takes up 66.8% of physical memory.

However, Filesystemcache What is the maximum amount of physical memory to occupy? The answer is:90%, from:

Filesystemcache The corresponding operating system parameters, you can use the operating system command Vmo-a-F(for aix6.1) to view, mainly these parameters:

Maxclient%=20

Maxperm%=20

Maxpin%=80

Minperm%=5

Strict_maxperm=0

Strict_maxclient=1

The above parameter values come from engineering practice.

It is worth noting that in all official documents of Oracle and in all official documents of IBM,maxclient% and maxperm% are required to keep the default values (i.e.:90%). In engineering practice, keeping the default values is a big problem. I have always suspected that keeping the default is the "conspiracy" of the United States---let domestic customers spend money, buy a small machine, but can not effectively use physical memory (that is, let the file system buffer occupy physical memory), rather than technical requirements.

About the Filesystemcache on AIX