Apache Limiting Connections Per VHOST

Solution 1:

Apache does not limit connections per Virtual Host, not unless you are using an extra 3rd party module.

What is happening is your MPM settings (as above) have a limit on the maximum number or requests/connections that will be allowed in terms of how may processes (or threads) are used.

What you do next depends on which MPM you are using... One that is thread based, one that is process based, how PHP is set up (as a separate process / cgi, or as an Apache module), etc.

http://httpd.apache.org/docs/2.2/mod/worker.html

http://httpd.apache.org/docs/2.2/mod/prefork.html

Also try playing with the KeepAlive settings.

KeepAlive On
KeepAliveTimeout 1

Solution 2:

mod_cband can do this, http://codee.pl/cband.html

You would see it in the form of lines like this in your virtualhost:

    # limit speed of this vhost to 10Mbit/s, 10 request/s, 30 open connections
    CBandSpeed 10Mbps 10 30

Since you are trying to ensure it doesn't happen, this may not be it, but this is something to look for.