Apache keeps going down: server reached MaxRequestWorkers setting

Created:

2016-12-12 03:48:54 UTC

Modified:

2017-08-19 08:40:35 UTC

10

Was this article helpful?


Have more questions?

Submit a request

Apache keeps going down: server reached MaxRequestWorkers setting

Applicable to:

  • Plesk 12.5 for Linux
  • Plesk Onyx for Linux

Symptoms

After execution of Plesk daily maintenance task, Apache is restarted and then stops responding. The following error can be found in /var/log/apache2/error.log:

[mpm_prefork:error] [pid 14998] AH00161: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting

Cause

The MaxRequestWorkers limit has been reached.

Resolution

  1. As a first step make sure that the workarounds from the following articles has been applied:
    KB#213946305
    KB#115001305105

    If the issue still persists continue with tuning of Apache web server as below
  2. Increase the MaxRequestWorkers and ServerLimit limits in the corresponding file which depends on Multi-Processing Module. For example:

    For Debian-based OS:

    # grep Worker /etc/apache2/mods-enabled/mpm_prefork.conf
    MaxRequestWorkers 300
    ServerLimit 300

    For RHEL-based OS:

    # cat /etc/httpd/conf.modules.d/01-cgi.conf 
    ...
    <IfModule mpm_prefork_module>
    LoadModule cgi_module modules/mod_cgi.so
    MaxRequestWorkers 400
    ServerLimit 400
    </IfModule>
    ...

    Note: for each Multi-Processing Module, values will be different.

  3. Restart Apache service.

    Note: Be careful, too high values of MaxRequestWorkers and ServerLimit directives may cause Apache to become unresponsive.

Additional Information

More about MaxRequestWorkers directive:

 

Have more questions? Submit a request

1 Comments

Please sign in to leave a comment.