Apache service failed to start
1. Apache failure phenomenon
Because Apache has been hot-deployed with reload before, some mutex semaphores may not be released, making it impossible to apply. Sometimes it will cause apache startup / load to fail, and report some errors as below->
[Mon Jul 04 14:13:59.260922 2016] [core:emerg] [pid 27103] (28)No space left on device: AH00023: Couldn't create the rewrite-map mutex
[Mon Jul 04 14:13:59.260946 2016] [:emerg] [pid 27103] AH00020: Configuration Failed, exiting
2. Solution
Then execute the following statement to release the synchronization semaphore
ipcs | grep apache | awk '{print $2}' > signal.txt
for i in `cat signal.txt` ; do { ipcrm -s $i; } ; done;
3. Restart apache again to solve