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From Jeff Trawick <>
Subject Re: [users@httpd] apache hanging whole system
Date Mon, 17 May 2010 15:19:24 GMT
On Sun, May 16, 2010 at 4:42 PM, Peter Halicky <> wrote:
> Hi,
> I run a "LAMP" server with a few websites, one of them quite busy. I use
> Ubuntu 8.04 with apache 2.2.8
> and PHP 5.2.4. The problem is this: about once a day, apache processes
> cause the system load to go very
> high (today it was ~30). During this time, I can not display any webpage
> on my server. If I do not notice, the
> problem goes away after 3-10 minutes. If I do notice, I can ssh into the
> server (if I'm lucky and I get a connection,
> which could be a problem with sysload over 30+), I kill all apache
> processes (very many of them, usually equal
> to MaxClients), restart and everything is fine (with sysload rarely
> above 2, usually around 0.5).
> I use the prefork MPM with the following settings (just for the record):
>    StartServers          5
>    MinSpareServers       5
>    MaxSpareServers      10
>    MaxClients           80
>    MaxRequestsPerChild  10

Death by fork()

Did you really intend to throw away and recreate a child process after
it handles only 10 requests?

MaxRequestsPerChild as a preventative measure:  this is generally in
the 10s of thousands (e.g., MaxRequestsPerChild 50000)

MaxRequestsPerChild to solve an actual resource problem: this is
generally in the thousands (e.g., MaxRequestsPerChild 4000)

If the third-party software loaded into or otherwise run inside httpd
really can't handle more than 10 requests before leaking so much
memory or other resources that the process has to exit to clean up the
resources immediately, throw it away.

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