ORA-12547: TNS:lost contact

Cause : This error occur when oracle database resource owner in not oracle user.

Action : Connect your server as root user and perform the following.

[root@micrsvr db_1]# chown -R oracle:oinstall /u01
[root@micrsvr db_1]# chmod -R 775 /u01
[root@micrsvr db_1]# su oracle

[oracle@micrsvr ~]$ sqlplus /nolog

SQL*Plus: Release 11.2.0.1.0 Production on Thu Jul 18 13:18:20 2013

Copyright (c) 1982, 2009, Oracle.  All rights reserved.

SQL> conn /as sysdba
Connected to an idle instance.
SQL> startup
ORACLE instance started.

Total System Global Area  935317504 bytes
Fixed Size                  2218912 bytes
Variable Size             692061280 bytes
Database Buffers          234881024 bytes
Redo Buffers                6156288 bytes
Database mounted.
Database opened.
SQL>