Datafile copies exist on disk only. To back up a datafile copy:. You can back up the control file when the database is mounted or open. RMAN uses a snapshot control file to ensure a read-consistent version. The control file autobackup contains metadata about the previous backup, which is crucial for disaster recovery.
If the autobackup feature is not set, then you must manually back up the control file in one of the following ways:. A manual backup of the control file is not the same as a control file autobackup. In manual backups, only RMAN repository data for backups within the current RMAN session is in the control file backup, and a manually backed-up control file cannot be automatically restored. In this example, the default configured channel is to an sbt device.
This command backs up tablespace users to tape and includes the current control file in the backup:. If the database is open, shut down the database normally if possible. In this case, you will need to recover from the loss of the redo logs step 8. If you are creating the control file as part of recovery, recover the database.
If you have lost online redo logs, archived redo log files, or data files, use the procedures for recovering those files. Oracle Database Backup and Recovery User's Guide for information about recovering your database and methods of recovering a lost control file. If you did not perform recovery, or you performed complete, closed database recovery in step 8 , open the database normally. After creating a new control file and using it to open the database, check the alert log to see if the database has detected inconsistencies between the data dictionary and the control file, such as a data file in the data dictionary includes that the control file does not list.
If a data file exists in the data dictionary but not in the new control file, the database creates a placeholder entry in the control file under the name MISSING nnnn , where nnnn is the file number in decimal.
In this case, you must drop the tablespace containing the data file. Conversely, if a data file listed in the control file is not present in the data dictionary, then the database removes references to it from the new control file. In both cases, the database includes an explanatory message in the alert log to let you know what was found. In this case, you should restore the files you backed up in " Creating New Control Files " and repeat the procedure in that task, using the correct file names.
Back up the control file to a binary file duplicate of existing control file using the following statement:. This command writes a SQL script to a trace file where it can be captured and edited to reproduce the control file. View the alert log to determine the name and location of the trace file. Oracle Database Backup and Recovery User's Guide for more information on backing up your control files. You can drop control files, but the database should have at least two control files at all times.
You want to drop control files from the database, for example, if the location of a control file is no longer appropriate. This operation does not physically delete the unwanted control file from the disk. Use operating system commands to delete the unnecessary file after you have dropped the control file from the database.
August 30, - am UTC. December 03, - am UTC. Robert, March 15, - pm UTC. Tom, As a follow up to Anil's question and your response from August 30, Then why even backup a binary controlfile? The binary backup and the new controlfile from 'trace' behave identically. By using a new controlfile you do not have to open the database using 'resetlogs'. Am I correct? Thanks, Robert. March 15, - pm UTC. If so, is there a nice and easy method to use a trigger perhaps at the Database level to issue the command, following DDL?
Thanks in advance for any help. April 05, - am UTC. No, most ddl doesn't change the physical structure of the database.
Richard, April 05, - am UTC. Taking Backup and reusing control file on different oracle instance. Burleson is the American Team Note: This Oracle documentation was created as a support and Oracle training reference for use by our DBA performance tuning consulting professionals.
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