i am facing this error when i start the oracle. I checked Oracle Home and SID. everything is set properly.
ORA-27101: shared memory realm does not exist
please help me to find out the solution. Thanks in advance
That error generally means there's no Oracle instance (the processes) to connect to. Someone needs to log in and start the instance.
I've just resolved this issue on Debian.
If ORACLE_HOME has a trailing slash, this error appears. If you remove the trailing slash, connection works fine.
来源：https://stackoverflow.com/questions/3302941/ora-27101-shared-memory-realm-does-not-exist