How to fix ORA 27101 shared memory realm does not exist?

Scenario 1: Invalid ORACLE_HOME and ORACLE_SID: ORA-27101 is usually due to the invalid ORACLE_HOME and ORACLE_SID parameters at OS level. You should investigate that ORACLE_HOME and ORACLE_SID are set correctly, and ORACLE_HOME should be without trailing slash.

How to fix ORACLE not available error?

If you believe the problem is the result of upgrading Oracle, you can check two files (/etc/oratab and /var/opt/oracle/oratab) for an invalid entry. Match the ORACLE_HOME and ORACLE_SID in these files. If they do not match, this needs to be resolved in order to resolve the error.

How do I start a database?

To start or shut down Oracle Database:

Go to your Oracle Database server.
Start SQL*Plus at the command prompt: C:\> sqlplus /NOLOG.
Connect to Oracle Database with username SYSDBA: SQL> CONNECT / AS SYSDBA.
To start a database, enter: SQL> STARTUP [PFILE=path\filename]
To stop a database, enter: SQL> SHUTDOWN [mode]

How do you fix Ora 27101?

ORA-27101 is often thrown along with ORA-01034 during database installation. ORA-27101 is also seen after installation is complete, when attempting to use SQL*Plus. To resolve this issue with ORA-27101, you should be sure that ORACLE_HOME and ORACLE_SID are correct, and ORACLE_HOME should not have trailing slash.

What is the path for Oracle_home in Windows?

On Windows platform you can find oracle_home path in the registry. There you can see oracle_home variable. On cmd, type echo %ORACLE_HOME% . If ORACLE_HOME is set it will return you the path or else it will return %ORACLE_HOME% .

How do I start a Windows database service?

How do I run Oracle?

Do one of the following:

On Windows: Click Start, point to Programs (or All Programs), point to Oracle Database 11g Express Edition, and then select Start Database.
On Linux with Gnome: In the Applications menu, point to Oracle Database 11g Express Edition, and then select Start Database.

What does Oracle not available ora-01034 mean?

Sometimes you can get ” ORA-01034: ORACLE not available ORA-27101: shared memory realm does not exist ” error. Details of error are as follows. Cause: Oracle was not started up.

Where to find Oracle Sid in ora-01034?

Search for ORACLE_SID using ‘echo $ORACLE_SID’ for Unix and by right-clicking the My Computer tab in Windows, clicking on Properties, then the Advance tab, and finally the Environment variable. You may find that ORACLE_SID is undefined or left blank, which is causing your ORA-01034 error.

Why do I get an oracle not available error?

An ORA-01034 error is triggered due to the Oracle system not being available or started up. This could derive from the System Global Area (SGA) necessitating more storage space than what is currently being allocated for your Oracle database. It could also be that operating system variable pointing to the instance was not properly defined.

Where do I find invalid entry in Oracle?

How to fix ORA 27101 shared memory realm does not exist?