I'm unable to determine, how many users my apache instance can handle.
I installed Apache 2.4.18 from Ubuntu repository, as far as I remember, all settings are default ones.
I did a server stress test and discovered, that when exceeding 300 ongoing requests, server start to drop new ones, serving response code 502 or 504.
I tried to find an explanation for that in server configuration file and documentation, but I was unable to discover where that "300" came from.
mpm_prefork, with config file like this:
<IfModule mpm_prefork_module> StartServers 5 MinSpareServers 5 MaxSpareServers 10 MaxRequestWorkers 150 MaxConnectionsPerChild 0 </IfModule>
Some of the properites from
Timeout 300 KeepAlive On MaxKeepAliveRequests 500 KeepAliveTimeout 5
So the question is what is Apache DEFAULT max concurrent clients limit in my (default) configuration? I'm not interested in tuning Apache to handle as many connections as possible - only to understand, how Apache calculates max concurrent clients limit.