[CentOS] CentOS 3 vs. CentOS 4 Memory Utilization

[Craig White]

On Thu, 2007-02-08 at 22:33 -0500, hkclark at gmail.com wrote:
> I'm helping some folks who have a CentOS 3 i386 server with 512MB of
> RAM.  The output of 'free' looks like:
> 
> $ free
>              total       used       free     shared    buffers     cached
> Mem:        511428     497956      13472          0      29868     178280
> -/+ buffers/cache:     289808     221620
> Swap:      2040244     120644    1919600
> 
> The box does not even have X installed... it's basically a web
> application and email server.  They would like to upgrade to CentOS 4,
> but are concerned that it could be considerably more "memory hungry"
> and lead to memory starvation (they don't want to add more RAM to the
> box at this time, although that could be an option down the road).
> 
> I ran some tests under VMWare with fresh installations of CentOS 3 and
> CentOS 4 (both using a "minimal install", the same as the server in
> question) and CentOS 4 seemed to only use 10-25MB more memory.
> However, it's hard to know how this will translate into real-world
> performance over time and with the application installed.
> 
> Does anyone have any experience that would suggest how much more
> memory a non-X server like this might require?  If the application(s)
> on the server stay the same, do you think we would run into issues
> where memory would be depleted to a level that would cause concern?
---
I wouldn't think so, this system actually does have some x-stuff
installed.

# cat /etc/redhat-release
CentOS release 4.4 (Final)

# free
             total       used       free     shared    buffers
cached
Mem:        515604     509760       5844          0      37832
117296
-/+ buffers/cache:     354632     160972
Swap:      1048568     268324     780244

It's running
httpd/php5/mysql-4/postfix/amavisd-new/ejabberd/ntp/cupsd/apcupsd
(slave)

Craig