ORA-10997: another startup/shutdown operation of this instance inprogress

SQL> startup
ORA-10997: another startup/shutdown operation of this instance inprogress
ORA-09968: unable to lock file
Linux-x86_64 Error: 11: Resource temporarily unavailable


Delete or rename the file $ORACLE_HOME/dbs/lkinst<instance_name>
A new file will be created when the instance is started up again.

Then startup normal

$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.2.0 Production on Sat Sep 20 20:36:34 2014

Copyright (c) 1982, 2010, Oracle.  All rights reserved.

Connected to an idle instance.

SQL> startup
ORACLE instance started.

Total System Global Area 4275781632 bytes
Fixed Size                  2233336 bytes
Variable Size            2969570312 bytes
Database Buffers         1291845632 bytes
Redo Buffers               12132352 bytes
Database mounted.
Database opened.