Plesk under Virtuozzo 4.0 hitting MaxClients

[danbell]

I have a CentOS5 x86_64 machine with dual 2.33 quad core Xeon CPUs and 4GB of RAM running Plesk 8.6.0 under Virutozzo 4.0. The system is not busy. No real load and memory usage is about 248MB. However, I keep hitting MaxClients for httpd, regardless of what I increase the MaxClients and ServerLimit to. One funny thing I did notice was that if I specified, say 20 or 40 StartServers, it doesn't seem to wind up with that many processes. In fact, I have not seen more than 11 httpd processes running at one time. I tend to hit MaxClients within 5 or 10 seconds of an apache restart, even though I only have 50-100 hits. This is my current httpd.conf

<IfModule prefork.c>
StartServers 50
MinSpareServers 25
MaxSpareServers 50
ServerLimit 512
MaxClients 512
MaxRequestsPerChild 4000
</IfModule>

# worker MPM
# StartServers: initial number of server processes to start
# MaxClients: maximum number of simultaneous client connections
# MinSpareThreads: minimum number of worker threads which are kept spare
# MaxSpareThreads: maximum number of worker threads which are kept spare
# ThreadsPerChild: constant number of worker threads in each server process
# MaxRequestsPerChild: maximum number of requests a server process serves
<IfModule worker.c>
StartServers 50
MaxClients 512
MinSpareThreads 25
MaxSpareThreads 75
ThreadsPerChild 25
MaxRequestsPerChild 4000
</IfModule>


Am I missing something here. Is this a Plesk apache binary limit? Is there something I'm doing wrong in Virtuozzo? Ideas? Thanks.

 

[faris]

Plesk uses Centos's Apache for websites -- there's no Plesk-specific binary so that's one less thing to worry about.

Are you modifying the right file? /etc/httpd/conf/httpd.conf ?

What does apache say when it starts up in /var/log/httpd/error_log ?

There are two parameters that might technically affect the numbers of processes in a Virtuozzo Container - avnumproc and numproc. But I doubt either of these will be set too low and I would expect you to see a sigificant error message if they did come into play.


Faris.

 

[danbell]

I am modifying /etc/httpd/conf/httpd.conf.

/var/log/httpd/error_log reports the following.
[Mon Nov 03 14:53:48 2008] [notice] Apache/2.2.3 (CentOS) configured -- resuming normal operations
[Mon Nov 03 14:53:53 2008] [error] server reached MaxClients setting, consider raising the MaxClients setting


As for Virtuozzo settings. Avnumproc and Numproc are not limited.

 

[faris]

I can't think of anything else off-hand. Very strange. Sorry :-(

 

[danbell]

I've got it. You need to modify /etc/httpd/conf.d/swtune.conf in the container holding Plesk. It has configuration directives which override /etc/httpd/conf/httpd.conf. You must restart apache to make the changes take effect.

 

[faris]

OK, thats bloody strange. I've not come accross that file before.

In fact it looks like the majority of our containers don't have it.

Two of them do though and both are Centos 5. The file has no contents in itself -- it links back to the swtune.conf file in the Centos 5 template, which obviously means any changes made to it will affect all containers running under that template.

I'd be tempted to delete it.

Faris.