This error may occur in many circumstances you need to check environment variables:
$ORACLE_HOME
$ORACLE_BASE
$ORACLE_SID
also check /etc/hosts file it must contains correct hostname and ip.
example:
$ORACLE_HOME
$ORACLE_BASE
$ORACLE_SID
also check /etc/hosts file it must contains correct hostname and ip.
example:
[oracle@oel6 ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.3.0 Production on Mon Jan 27 11:55:17 2014
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup;
ORA-00000: normal, successful completion
after that i checked environment variables:[oracle@oel6 ~]$ echo $ORACLE_BASE
/u0/app/oracle
[oracle@oel6 ~]$ echo $ORACLE_HOME
/u0/app/oracle/product/11.2.0/dbhome_1
[oracle@oel6 ~]$ echo $ORACLE_SID
orcl
it’s correct, then checked /etc/host filecat /etc/hosts
#10.10.1.176 oel6
bingo! someone maybe system administrator or other dba commented this
machine hostname and ip, hence we can’t start database, uncomment it
and everything goes correct.vi /etc/hosts
10.10.1.176 oel6
sqlplus / as sysdba
SQL*Plus: Release 11.2.0.3.0 Production on Mon Jan 27 12:03:10 2014
Copyright (c) 1982, 2011, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup;
ORACLE instance started.
Total System Global Area 835104768 bytes
Fixed Size 2232960 bytes
Variable Size 645926272 bytes
Database Buffers 180355072 bytes
Redo Buffers 6590464 bytes
Database mounted.
Database opened.