- Plesk for Linux
Loading the website takes too much time or finishes with "504 Gateway Time-out" error. The following error appears in the
CONFIG_TEXT: [error] server reached MaxClients setting, consider raising the MaxClients setting
[warn] mod_fcgid: process 2968 graceful kill fail, sending SIGKILL
The connections limit defined by
MaxClients is reached.
Connect to the server via SSH.
By default, Apache in Plesk is not configured for high-loaded sites. It is recommended to tune Apache performance as it described here: http://httpd.apache.org/docs/2.2/misc/perf-tuning.html or https://httpd.apache.org/docs/2.4/misc/perf-tuning.html
To resolve the issue with the
MaxClientslimit, adjust the
/etc/httpd/conf/httpd.conf(/etc/apache2/conf/apache2.conffor Debian 7/Ubuntu 12/14) file on SystemV OSes (CentOS 6 or lower), increasing the
MaxClientsvalue (e.g., to 100):
CONFIG_TEXT: <IfModule prefork.c>
CONFIG_TEXT: <IfModule worker.c>
Note: For CentOS 7, file
/etc/httpd/conf.d/mpm_prefork.conf should be edited instead of <IfModule prefork.c> section. If the error persists, consider increasing
MaxClients limit again until the issue is fixed.
For Debian 8 and 9/Ubuntu 16 and 18, use the following files
If the error is still shown, check all files where
MaxClients directive defined. It can be done with the following command:
# grep -iRl "MaxClients" /etc/
If there is no such option at all, add it manually to files listed above.
MaxClients directive was the name for
MaxRequestWorkers directive before version Apache 2.3.13:
CONFIG_TEXT: * MaxClients has been renamed to MaxRequestWorkers, which describes more accurately what it does. For async MPMs, like event, the maximum number of clients is not equivalent than the number of worker threads. The old name is still supported.