ORA-27100: shared memory realm already exists oracle 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.
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.