Article ID: 6460, created on Jun 19, 2009, last review on Nov 24, 2014


Apache crash on high load with the following error in the error log:

(28) No space left on device: mod_python: Failed to create global mutex 1 of 4  exclog: signal received 15


The problem may be caused by small number of semaphores in system.


Increase number of semaphores. Additionally switch AcceptMutex method to fcntl (Apache 1.3.21 and later only)To increase the number of semaphores please take the following steps:

  1. Login to your PPCPL server as root
  2. Open the /etc/sysctl.conf file using a text editor
  3. Locate the kernel.sem parameter and double current values
  4. If the parameter is not defined in the /etc/sysctl.conf file you can obtain current values by executing the following command:

    cat /proc/sys/kernel/sem

After obtaining current values, double them and add to the /etc/sysctl.conf file so that the line looks like

kernel.sem = 512 32000 100 512

Please note, values for your installation may vary.

  1. Execute sysctl in order the changes to take effect

    sysctl –p

To change the AcceptMutex method please take the following steps:

  1. Log as root to your PPCPL box
  2. Open the /etc/httpd/conf/httpd.conf configuration file using a text editor
  3. Locate the AcceptMutex directive and change it to the following

    AcceptMutex fcntl

  4. If the directive is not present in your /etc/httpd/conf/httpd.conf configuration file please add it on the server config context

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