On Fri, 2 Nov 2007 7:47 am, Gary Sewell wrote:
Firstly, we are running a mod_perl application on 4 separate servers due to its bulkiness.

How many requests per second are you processing with each machine? Have you looked at profiling your application?

We have found each apache instance is almost double on the 64-bit servers
Example 64-bit

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND

www-data  9950  2.4  1.7 210324 141744 ?       S    14:26   0:11  \_ /usr/sbin/apache-perl

Example 32-bit

USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND

www-data  2336  0.0  2.7 117100 105908 ?       S    15:14   0:16  \_ /usr/sbin/apache-perl

Is this something we just put up with or have we done something drastically wrong?

Iirc, the calculations for shared memory on linux aren't always accurate, but toersten may have released something that addressed this, linux::smaps I think. As a comparison, I have commonly seen apps that take over 500 megs total process memory, but most of that is shared or data. I've seen java apps or php apps take up comparatively as much memory.

Is it worth installing a 32-bit distribution on the 64-bit processors? Will the 8Gb RAM cause problems as 32-bit distributions if we did this?

Probably not worth it. I run mod_perl on a 64 bit machine with 16 gigs and no problems.

How can I get a split/rundown of what is taking up so much memory for each apache instance, 100Mb is a lot, let alone 200Mb on the 64 bit servers. I’m sure we are going wrong somewhere.

Apache2::Status will give you a detailed breakdown of where your memory is used.



Many Thanks.

GS

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