On Tue, Sep 18, 2018 at 12:14:11AM +0200, Martin wrote: > I have an issue with Apache's HTTP-Server 2.4. It says 'Resource temporarily > unavailable: AH00159: fork: Unable to fork new process'. I know, there are > some hits with Google, but there is no solution to me. > Systemd knows about a task limit of 6000. mpm_prefork_module is set to > 'ServerLimit 4000' and 'MaxRequestWorkers 4000'. ulimits are set to unlimited. > I also see in the kernel log 'cgroup: fork rejected by pids controller in > /system.slice/apache2.service'. But this does not correlate with the httpd's > messages from above, that comes only from time to time. > Why does this thing stop forking at about 3000 processes? I have a (not just > one) Red Hat 6 in parallel, that one does.
"fork: Unable to fork new process" sounds to me like a system-level error, coming from fork itself, not an apache configuration issue per se. Have you checked for available resources on the system? Apache processes are fairly heavy in terms of memory and CPU usage, so I'd expect you to need a real beast of a machine to handle even 3000 apache processes, never mind 6000. -- Dave Sherohman
