Filesystemcache and aixfilesystemcache on aix

Filesystemcache and aixfilesystemcache on aix

The filesystemcache on aix has been discussed in the following books:

 

The Oracle optimization Diary of eel: The story of a gold card dba.

See page 165th:

 

This FileSystemCache, after nmon enters, you can see it after hitting m. The following is an example:

 

Note:

FileSystemCache (numperm) 66.8%

Process 28.3%

System 4.8%

The sum of Free 0.2% and above is approximately 100%

That is to say, the distribution of all physical memory usage is shown here.

 

Note:

FileSystemCache (numperm) actually occupies 66.8% of the physical memory.

But how much physical memory does FileSystemCache occupy? The answer is: 90%, from:

 

 

The operating system parameters corresponding to FileSystemCache can be viewed using the operating system command vmo-a-F (for aix6.1). These parameters are mainly used:

 

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 oracle official documents and in all IBM official documents, maxclient % and maxperm % both require the default value (I .e., 90% ), in engineering practice, it is very difficult to retain the default value. I have always suspected that the default value is the "conspiracy" of the US Emperor-making domestic customers spend money and buy a small machine, but they cannot effectively use the physical memory (I .e: physical memory usage by file system buffering), not technically required.