[users@httpd] Settings for memory conservation

["Harrell, Roger" <rj...@bechtel.com>]

I have a RH9 box running Apache with 512MB RAM. Occasionally the server gets
slammed by crawlers and ends up getting hosed up due to reaching full memory
usage, then going to swap. I've looked at the various docs on tuning Apache
and so forth, but can not seem to figure out how to set things to prevent
this occurrence. I understand that when I reduce maxchilds and related
settings when the server gets slammed web access will slow, but as it stands
right now all services on the box get hosed. Anyway, what occurs is that
several of the httpd child processes exceed 10% memory usage. When enough of
this happens I run into this problem. How can I ensure that total httpd
memory usage will never exceed say 450MB?

I can not find any way of determining a good value for MaxClients. The docs
do not seem to by any help here. Any pointers?

Thanks,
Roger

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Re: [users@httpd] Settings for memory conservation

[Joshua Slive <js...@gmail.com>]

On Mon, 3 Jan 2005 10:55:33 -0800, Harrell, Roger <rj...@bechtel.com> wrote:
> I have a RH9 box running Apache with 512MB RAM. Occasionally the server gets
> slammed by crawlers and ends up getting hosed up due to reaching full memory
> usage, then going to swap. I've looked at the various docs on tuning Apache
> and so forth, but can not seem to figure out how to set things to prevent
> this occurrence. I understand that when I reduce maxchilds and related
> settings when the server gets slammed web access will slow, but as it stands
> right now all services on the box get hosed. Anyway, what occurs is that
> several of the httpd child processes exceed 10% memory usage. When enough of
> this happens I run into this problem. How can I ensure that total httpd
> memory usage will never exceed say 450MB?
> 
> I can not find any way of determining a good value for MaxClients. The docs
> do not seem to by any help here. Any pointers?

Normally you determine MaxClients by dividing your available RAM
(minus requirements for the OS and other programs) by your average
apache process size determined by ps or top.  In your case, it seems
like you also have some script that is using more than its fair share
of RAM.  You should probably identify the offending process (using
ps/top), then use mod_status to figure out what script is the problem
and fix the script.

Joshua.

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