httpd and memory usage

Thomas Hurst tom.hurst at
Tue Jun 14 16:04:10 GMT 2005

* David Banning (david+dated+1118931663.a557d5 at wrote:

> I seem to have a lot of memory being eaten by httpd (part output of top);

> Any ideas to have httpd timeout sooner to preserve memory?

MaxRequestsPerChild is there to cope with leaks, it won't help if Apache
is using a lot of memory to start with though, but if you've got some
mod_php or mod_perl which leaks it can be handy.

Worker MPM uses threads and will probably share more memory than
prefork, not to mention require you to use fewer processes to handle a
given load.

Moving things like mod_php and mod_perl stuff to FastCGI avoids each
httpd having a copy of the interpreter and its various data structures
each, and segments the memory of the interpreters outside httpd so it's
easier to see what's using the memory; you'll have fewer copies running
too, since the static:dynamic request ratio isn't normally 1:1.

Commenting out unused modules in httpd.conf will save some memory.

You might also consider switching to something like lighttpd, which uses
a single process that's generally about 1/3 the size of an equivilent
httpd process.

Thomas 'Freaky' Hurst

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