[CentOS] 2.6 memory management question

John R Pierce pierce at hogranch.com
Tue Apr 10 16:47:04 UTC 2007


tblader wrote:
> [2]$ cat /proc/meminfo
> MemTotal:      7128956 kB
> MemFree:       2132556 kB
> Buffers:        556832 kB
> Cached:        2821408 kB


you do realize, out of that 7GB of ram, 2GB is unused entirely, and 
2.8GB is being used as disk cache, another 500MB as buffer space... so 
in fact program memory usage is down around 2-3GB ?


if you understand that, my apologies.   Its just that I've dealt with 
lots and lots folks who focus entirely on that "MemFree" line without 
realizing that "Cached" is also available as 'free' space.



btw, you said Oracle.   I've heard that if you enable huge pages w/ 
oracle on large memory x86_64 systems, you get a BIG performance 
boost.   sorry, I don't know the specifics, but there's probably a 
Oracle MetaLink article on it.



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