I'm trying to start our db after performing a shutdown abort on a oracle 10g server, but I'm getting the following message:

ORA-27100: shared memory realm already exists Linux Error: 17: File

Oracle 10g running under Centos 6.x

Anyone know any leads about solving that issue? I found this link but since I don't have a extensive background on oracle db administration I rather confirm if I should follow these instructions.

EDIT In 2017 : This is an old question when I was on a company that I no longer work for. Sadly I never had the change to solve this neither have the current scenario to reproduce this error.

  • Edit your question with the output of ipcs -a|grep oracle and ps auxww| grep pmon
    – Philᵀᴹ
    Commented Oct 17, 2014 at 11:43

2 Answers 2


Phil is right - you need to see if you have any orphan Oracle processes and ipcs shared memory.

If you have more than one Oracle instance on your server, include the instance in your grep commands; more than likely, you may have some orphan Oracle processes still running. Assuming your SID is custdev, you could do a

ps -fu oracle | grep custdev

and then do a kill -9 PID (where PID is the process ID) on any of the PIDs that show up.


Another way to resolve this issue is by checking and remove orphaned Oracle memory segments by executing sysresv utility or by deleting all not used semaphores and shared memory of Oracle user by executing a script which you can take here - https://stackoverflow.com/questions/2143404/delete-all-shared-memory-and-semaphores-on-linux

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.