Oracle11g reports an error when starting the database ora-27154: post/wait create failed

ORA-27154: post/wait create failed
This error is caused by the failure to obtain the operating system semaphore during startup （ Semaphores can be understood as memory locks ）, When a process needs to use memory, it must first obtain a semaphore before applying for memory .
Generally during installation ,oracle Medium processes Parameter set to processes*2+15 It's safe .

Usually report an error ORA-27154: post/wait create failed There are also several errors ：
ORA-27300: OS system dependent operation:semget failed with status: 28
ORA-27301: OS failure message: No space left on device
ORA-27302: failure occurred at: sskgpcreates
These errors are reported because processed Too big , The semaphore to be acquired is not enough, resulting in .

View current settings
[[email protected] oracle]$ cat /proc/sys/kernel/sem
250 32000 100 128

4 The data correspond to ：SEMMSL SEMMNS SEMOPM SEMMNI
The specific meaning is not explained here , Just say the modification scheme .

take sem Is changed to ：5010 641280 5010 128

If you need to apply it automatically when starting , Can be found in /etc/sysctl.conf increase ：
kernel.sem =5010 641280 5010 128

sysctl -p