Originally posted by: MuhammadShahid

Hi,
I am using AIX 5.3 on production server. It is showing fscashe 100 percent most of the time. Server performance become slow. According to IBM document fscache can use up to 80% of RAM. I just want to know that what is behavior of it.
1- I just want to know this 80% fscache usage of RAM is part of complete
physical RAM or remaining RAM after assign the RAM to database.
2- Can we change this 80% to 0% what will be impact on AIX performance and
database or applications running on that system.

Shahid

Originally posted by: niella

Hi,

You are right to want to revise this if you are running a database server like Oracle or DB2, but not in the way you mentioned.

You should instead run:
vmo -p -o minperm%=3 -o maxperm%=90 -o maxclient%=90 -o lru_file_repage=0

This should be safe to do unless you are also running a web-server or some other type of application for which the file cache is important.

Refer to http://www.ibm.com/developerworks/wikis/download/attachments/53871915/VMM+Tuning+Tip+-+Proctecting+Comp+Memory.pdf?version=2

Regards,
Niel

Originally posted by: cd3lgado

Hi

Depending on the Maintenance level (or tech level) your server has installed on you need to do some tuning using the vmo command.

I always use the following settings:

maxperm=8
maxclient=8
minperm=3

I have seen better use of the memory resources using these numbers than using the ones recommended by IBM once you have installed the latest tech levels available in the IBM AIX page. Of course is a matter of testing which set of parameters solve you problems.

HTH