UNIX for Dummies Questions & Answers

Hi All

I have a clarification. I am running a database on CentOS 4.5 final, PostgreSQL version 8.1.9. The question is about memory usage on the system. The memory used statistic has risen consistently over the past few days... by about 2-3% a day. I want to know why this memory is growing. The system has 8 GB of memory... Also I checked the % of user memory used... that remains low.

I want to explain why the memory used is growing? I know that the kernel keeps the memory in buffer and cache. But at what point does this buffer get initialized. Is this memory available for other user processes? Is memory used the right static to track?

sar tells me the following:
%user 0.22
%nice 0.00
%system 0.08
%iowait 0.41
%steal 0
%idle 99.29

kbmemfree 0.37
kbmemused 3.48
buffers 0.18
kbcached 3.06

I want to know when the cache will clear up? What is the logic of cacheing?

Please point me to an article or something.

Regards

Srini

Here's a well written article, I guess it will shed some light. And another one, from Gentoo's Wiki.