How to clear Apache httpd semaphores

Solution Verified - Updated -


  • While using httpd, we receive the message when starting httpd; "No space left on device: Cannot create SSLMutex."
  • Apache was terminated and didn't clean up its semaphores.
  • How to identify the semaphores that are not being used by any process and remove them.


  • Apache httpd
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7

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