Control Files recovery

[krishna]

Hi,
When I try to startup my database, I get this error:

"ORA-00205 error in identifying controlfiles, check alert log for more details"

I had 3 control files in my parameter file and for debugging purposes, tried with each one but I'm getting the same error.

What should I do now??? I found from a book that the only solution if all the control files are corrupted, is to use this command:

"alter database backup controlfile to trace;"

and to get the proper "create controlfile" command and then to use it.

But, as I didn't understand this properly, wanted to clarify with u guys..

Could you please help me out.. Thanks in advance..

Regards,
krishna

[jmodic]

First, make sure you are modifying the correct init.ora when trying to bring up the database with at least one of your controlfiles.

If all of your controlfiles are realy corupted then I'm affraid you can't use ALTER DATABASE BACKUP CONTROLFILE TO TRACE, because it must be performed with database in MOUNT or OPEN state, which you can't do without a valid controlfile (catch22....).

So I belive your options are:

1. If you have backup of your controlfile in ASCII file (the output of the above command, should be part of any proper backup plan) you just have to run the CREATE CONTROLFILE command from this file, copy the created controlfile to previous locations and start the database.

2. If you are roning in archivelog mode you can restor controlfiles and datafile sfrom your backup, recover the database and open it with the RESETLOGS option.

3. The last option is to create new controlfile manualy. But you must know the names and location of each and any datafile and redolog file of your database. Run the CREATE CONTROLFILE command in NOMOUNT state, copy the generated controlfile to original locations with original names (or change the init_file parameter CONTROL_FILES) and open the database. To get you started more easily with the CREATE CONTROLFILE command I'm attaching the sample - you have to replace all the file names from your database, probably the characterset, archivelog mode, size of redolog files and any other stuff that is different in your database.

CREATE CONTROLFILE REUSE DATABASE "O815" NORESETLOGS NOARCHIVELOG
MAXLOGFILES 32
MAXLOGMEMBERS 2
MAXDATAFILES 1024
MAXINSTANCES 1
MAXLOGHISTORY 453
LOGFILE
GROUP 1 'C:\ORACLE\ORADATA\O815\REDO01.LOG' SIZE 1M,
GROUP 2 'C:\ORACLE\ORADATA\O815\REDO02.LOG' SIZE 1M
DATAFILE
'C:\ORACLE\ORADATA\O815\SYSTEM01.DBF',
'C:\ORACLE\ORADATA\O815\RBS01.DBF',
'C:\ORACLE\ORADATA\O815\USERS01.DBF',
'C:\ORACLE\ORADATA\O815\TEMP01.DBF',
'C:\ORACLE\ORADATA\O815\BONI01.DBF'
CHARACTER SET EE8MSWIN1250;

HTH,

[krishna]

Thanks a lot..I'll try ur suggestion..

Thanks again..

[sreddy]

consolidate concept of recreating controlfile....

[url]http://www.dbasupport.com/forums/showthread.php?threadid=5710&pagenumber=[/url]

[pando]

Hi

if you have online redologs you dont need to reset the logs, simply issue recover database after you create the controfile this should recover the database until point of failure.

[aarganesh]

Hi, if u'r db shutsdown normally, all u can do is, just overwrite the bad control file with one of the good control file. Remember 2 do this operation only when u'r DB is close NORMALLY
Rgds
Ganesh .R