Hi. I have a problem with my web server (Ubuntu 16.04 + ISPconfig 3.1). Every day or two 'apache' hangs and I need to reboot the server. The resources at there moment are in high level, but the server has 4GB of ram and no much traffic. The /var/log/apache/error.php shows this message before to the hang: [mpm_prefork:error] [pid 2178] AH00161: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting Another line that appears ocasinaly: [mpm_prefork:warn] [pid 2178] AH00167: long lost child came home! (pid 2186) I changed the value MaxRequestWorkers to 256 in /etc/apache2/mods-enabled/mpm_prefork.conf (default is 150) but the problem persists. Any idea of what happen? Thanks.
Check if the 'vlogger' package is installed and if not, try to install it with apt 'apt-get install vlogger' and then restart apache.
another possibility for this can be long running script processes like php processes. you can e.g. try to find them with the 'lsof -p' command.