This is one of the most commonly observed error in Oracle database. The exact error description is as follows:
ERROR:
ORA-01034: ORACLE not available
ORA-27101: shared memory realm does not exist
SUN OS Error: 2: No such file or directory
Due to this error, the DBA is unable to login to the SQL prompt. This error is usually caused because of the restricted permission of tnslsnr file in the Oracle DB. While this error is being encountered, the file permissions look as follows:
mms1% ls -l tnslsnr
-rwxr-x–x 1 oracle dba 2791568 Feb 6 2005 tnslsnr
mms1%
As you can see, the oracle user don’t have read/write permissions. To resolve the matter, change the permission as follows:
mms1% chmod 6750 tnslsnr
mms1%
The new permissions of the file look as follows:
mms1% ls -l tnslsnr
-rwsr-s— 1 oracle dba 2791568 Feb 6 2005 tnslsnr
mms1%
Now, if you try to login to SQL, there will be no error.
mms1% sqlplus "/as sysdba"
SQL*Plus: Release 9.2.0.5.0 – Production on Mon Apr 4 21:37:49 2011
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.5.0 – 64bit Production
JServer Release 9.2.0.5.0 – Production
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