How do I configure Linux to use less memory for IO caching?

Question

I'm running a Dell R310 with CentOS 5.8 x64 and all it's running is apache, svn, and postfix. It's using 99% of the RAM for caching but i'd like it to use a little less like maybe somewhere in the low 90s. How can I configure this?

Free memory is a waste. Why do you want it free? – Kyle Smith Apr 07 '12 at 00:23 — Kyle Smith, Apr 07 '12 at 00:23

score 7 · Answer 1 · answered Apr 07 '12 at 00:15

7

You really don't want to do this. The kernel will immediately relinquish cache pages to other applications if and when they call for it.

It's a complete waste of money to not let the kernel use all your available RAM.

answered Apr 07 '12 at 00:15

EEAA

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score 5 · Answer 2 · answered Apr 07 '12 at 00:15

5

Linux will use all the RAM that's available for caching, but when it needs it for anything else, it's just going to be freed from the cache, so you don't run out of memory because of the cache.

See this site for more info.

answered Apr 07 '12 at 00:15

Sven

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The reason I was asking was because our nagios was counting cached memory as "used" but the best solution to my issue is to get a better Nagios plugin. Thanks for taking the time to answer. – StackShin Apr 09 '12 at 19:01

How do I configure Linux to use less memory for IO caching?

2 Answers2