I have a VPS running apache-php-mysql on centos and a single drupal website installed. The VPS has 256MB of RAM (could be the root cause of all my problems... maybe I just need more). Whenever I try to open my website from multiple browser tabs (about 8... not 800) all at once, apache crashes! I have this on the log:

[Wed Oct 24 11:26:31 2012] [error] [client xxx] PHP Fatal error: Out of memory (allocated 28049408) (tried to allocate 201335 bytes) in xxx on line 2139, referer: xxx

I have read many many posts here, but I think there is something fundamental that I'm missing - If I understand correctly some php script tried to allocate 200K after allocating 28MB, and fails to do so.

First question is: should this cause the apache to crash???

Next, I tried to look at 'top' command while I do my little test. Indeed I see 7 httpd processes, each reserving about 30MB - which explains why my RAM runs out.

How do I prevent apache from creating new processes until it's out of memory?

I tried configuring /etc/httpd/conf/httpd.conf like this:

<IfModule prefork.c>
StartServers       1
MinSpareServers    1
MaxSpareServers    1
ServerLimit        1
MaxClients         1
MaxRequestsPerChild  100
</IfModule>

But got the same exact result!

What am I missing?

Thanks a lot!