Loss of control file

Question

Hi
My database is running on solaris 10. database verrison is 10.2.0.3.0
when connecting ot db after databases get started. it throws error
ORA-00205: error in identifying control file, check alert log for more info
and when I checked in alert log file
Thu Dec 25 18:39:04 2008
Errors in file /testdb/..n/../admin/../udump/mft_ora_7988.trc:
ORA-19502: write error on file "/oradb/../../arch/arch1_2162_623164752_MFT.log", blockno 30721 (blocksize=512)
ORA-27063: number of bytes read/written is incorrect
after browsing google I infer that we lost control file.
I dont have it backup
how do i recover it
Thanks in advance.

Answer 1

Do you have backup control file or auto backup control file by rman or not.
If you have backup, try recover controlfile from rman backup( you should know DBID).
Anyway If you don't have rman backup. so recreate controlfile (if you have backup control file to trace, you can use it):
1. Take a full backup of the database, including all datafiles and redo
log files.
2. Connect / as sysdba or as sys user and do a STARTUP NOMOUNT.
3. Issue the CREATE CONTROLFILE statement.
More information on Oracle.
http://www.oracle.com/pls/db102/homepage
     Example:
     CREATE CONTROLFILE REUSE DATABASE "TESTDB" NORESETLOGS NOARCHIVELOG
     MAXLOGFILES 50
     MAXLOGMEMBERS 3
MAXDATAFILES 300
MAXINSTANCES 8
MAXLOGHISTORY 500
     LOGFILE
     GROUP 1 '/oradata/testdb/log1.dbf' SIZE 100M,
          GROUP 2 '/oradata/testdb/log2.dbf' SIZE 100M,
          GROUP 3 '/oradata/testdb/log3.dbf' SIZE 100M
     DATAFILE
          '/oradata/testdb/system01.dbf' SIZE 400M,
          '/oradata/testdb/sysaux01.dbf' SIZE 500M,
          '/oradata/testdb/undotbs01.dbf' SIZE 100M ;
4. Perform media recovery on the database.
     RECOVER DATABASE
5. Open the database.
     ALTER DATABASE OPEN;
Good Luck.