Databases Reference
In-Depth Information
Restoring Control File Using Fast Recovery Area
Problem
You have enabled a fast recovery area (FRA), and you use it as a repository for your control file backups. You're
attempting to start your database and receive this error:
ORA-00205: error in identifying control file, check alert log...
You inspect the alert.log and determine that you've lost all of your control files and need to restore them.
Solution
When you use the FRA, you can use one of two very different methods to restore the control file depending on
whether you enabled the auto backup of the control file. This recipe describes both of these scenarios.
Using FRA and Autobackup Enabled
When you enable the auto backup of your control file and are using a FRA, then restoring your control file is fairly
simple. First connect to your target database, then issue a
startup nomount
command, and then issue the
restore
controlfile from autobackup
command:
$ rman target /
RMAN> startup nomount;
RMAN> restore controlfile from autobackup;
RMAN restores the control files to the location defined by your
control_files
initialization parameter. You
should see a message indicating that your control files have been successfully copied back from an RMAN backup
piece. Here is a partial snippet of the output:
channel ORA_DISK_1: AUTOBACKUP
/u01/fra/O12C/autobackup/2012_07_17/o1_mf_n_788860985_80bw4vbm_.bkp
found in the recovery area
■
The prior example works only if you have enabled the auto backup of the control file feature and are using a
FRA. You can verify whether the auto backup of the control file is enabled via the RMAN
show all
command. You can
verify whether the FRA is enabled by inspecting the
db_recovery_file_dest
initialization parameter.
Note
You can now alter your database into mount mode and perform any additional restore and recovery commands
required for your database.
Using FRA with Auto Backup Disabled
If you don't use the auto backup of the control file feature, then restoring the control file becomes more difficult. If
auto backup is disabled, you have to explicitly tell RMAN from which directory and backup piece to restore the control
