Guenadi N Jilevski's Oracle BLOG

ORA-00205: error in identifying control file

ORA-00205: error in identifying control file

Problem Description

Whenever you try to mount your database  it fails with ORA-00205 error message as below.
SQL> startup
ORACLE instance started.

Total System Global Area 535662592 bytes
Fixed Size 1334380 bytes
Variable Size 306185108 bytes
Database Buffers 222298112 bytes
Redo Buffers 5844992 bytes
ORA-00205: error in identifying control file, check alert log for more info

Error Investigation
As error message “ORA-00205: error in identifying control file, check alert log for more info” suggests  examine the   error stack in the alert log file following the error.

Based on this error message you might get various types of alert log entries which would really help you to solve your problem. Following is the several  error stack messages.

A.
ORA-00202: control file: ‘/oracle/controlfile/contro101.ctl’
ORA-27037: unable to obtain file status
Linux Error: 2: No such file or directory
Additional information: 3
Fri Feb 8 17:19:42 2008
ORA-205 signalled during: ALTER DATABASE MOUNT…
Fri Feb 8 17:19:50 2008
Shutting down instance (abort)

B.
ORA-00202: controlfile: ‘/u01/oracle/controlfile/CONTROL01.CTL’
ORA-27086: skgfglk: unable to lock file – already in use
OSD-04002: unable to open file
O/S-Error: (OS 5) Access is denied.

C.
ORA-00202: control file: ‘C:\ORACLE\CONTROL.CTL’
ORA-27047: unable to read the header block of file
OSD-04006: ReadFile() failure, unable to read from file
O/S-Error: (OS 38) Reached the end of the file.

D.
Errors in file /oracle/9.2.0/admin/bdump/abc_ckpt_3117.trc:
ORA-00206: error in writing (block 3, # blocks 1) of controlfile
ORA-00202: controlfile: ‘/oracle/data/ctl03.dbf’
ORA-27072: skgfdisp: I/O error
Linux Error: 30: Read-only file system
Additional information: 2

General Cause And Solution of ORA-00205 Problem:

The ORA-00205 problem is reported because the database could not find a control file with the specified name. The name of control file is specified by the CONTROL_FILES initialization parameter within spfile/pfile. While mounting the database oracle produces an error if the file specified by the CONTROL_FILES parameter is either missing or corrupted or with wrong permissions.

If you see ORA-00205  reported while mounting the oracle database then check that the proper control filename is listed in the CONTROL_FILES initialization parameter in the initialization file.  If not check the correct spfile/pfile or fix the location of CONTROL_FILES parameter within spfile/pfile and try again to mount the database.

Whenever you are using mirrored control files, that is, more than one control file is listed in the initialization parameter file, remove the control filename listed in the message from the initialization parameter file and restart the instance. If the message does not recur create another copy of the control file with a new filename in the initialization parameter file.

Step by step Solution

1.  After you see ORA-00205 immediately look for alert log files for further investigation.

2.  Check the control_files parameter in your initialization parameter. You can simply check by ,
SQL> show parameter control_files

Now compare this location with the location of controlfile in your disk system.

From the alert log if you see error message like version A i.e you have noticed “ORA-00202: control file: ‘/u01/oracle/controlfile/contro101.ctl'” then from your CONTROL_FILES initialization parameter remove the entry /u01/oracle/controlfile/contro101.ctl if you have multiple version of controlfiles and start the database. If you fail then again check for alert logs. If it is same error message like points to another controlfile then try to remove that control file too if you have at least three versions of controlfiles. If you fail then possibly all of your controlfiles are lost. In that case you need to restore controlfile from previous backup or create a new one if you don’t have any previous backup of controlfile.
If you see other version of error versions then take necessary actions as alert log suggests. For example if you see error message like version B that is
“ORA-00202: controlfile: ‘/oracle/controlfile/CONTROL01.CTL’
ORA-27086: skgfglk: unable to lock file – already in use”
then ensure that oracle database is shutdown cleanly and no other process is holding lock of the control file. After you ensure that try starting database again.

If you see error message like version C that is
“ORA-27047: unable to read the header block of file
OSD-04006: ReadFile() failure, unable to read from file”
then possibly your control file got corrupted and follow the same steps as it is demonstrated in step 2 for error version 01.

If you see error message like version D that is
“ORA-00202: controlfile: ‘/oracle/data/ctl03.dbf’
ORA-27072: skgfdisp: I/O error
Linux Error: 30: Read-only file system”
then ensure that your control file has proper permission set from operating system. That means it must have read, write permission to oracle owner user.

Summary:

After you identify and solve the problem make sure that you have multiple copies of your controlfile specified in the CONTROL_FILES parameter.

August 15, 2008 - Posted by gjilevski | oracle