When performing an RMAN recovery with only a single controlfile,
you may want to issue the USING BACKUP CONTROLFILE RMAN RECOVER
DATABASE command option.
If you must use a control file restored from the backup, you will
want to use the USING BACKUP CONTROLFILE option of the recover
command.
If you are using a backup control file with an incomplete
recovery, then specify the USING BACKUP CONTROLFILE option in the
RECOVER command.
SQL> RECOVER DATABASE UNTIL
CANCEL USING BACKUP CONTROLFILE;
SQL> RECOVER DATABASE USING BACKUP CONTROLFILE
UNTIL CANCEL;
The Oracle documentation notes restrictions on doing a
BACKUP
CONTROLFILE RECOVERY. The following notes and restrictions
apply regardless of whether you use a recovery catalog:
- You must run the RECOVER command after restoring a backup
control file, even if no datafiles have been restored.
- You must open the database with the RESETLOGS option after
performing either complete or point-in-time recovery with a
backup control file.
- If the online redo logs are inaccessible, then you must
perform incomplete recovery to an SCN before the earliest SCN in
the online redo logs. This limitation is necessary because RMAN
does not back up online logs.
- During recovery, RMAN automatically searches for online and
archived redo logs that are not recorded in the RMAN repository,
and catalogs any that it finds so that it can use them in
recovery.
RMAN attempts to find a valid archived log in any of the current
archiving destinations with the current log format. The current
format is specified in the initialization parameter file used to
start the instance (or all instances in a Real Application Clusters
installation). Similarly, RMAN attempts to find the online redo logs
by using the filenames as specified in the control file.
If you changed the archiving destination or format during
recovery, or if you added new online log members after the backup of
the control file, then RMAN may not be able to automatically catalog
a needed online or archived log. In this situation, RMAN reports
errors similar to the following:
RMAN-00571:===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS
===============
RMAN-00571:
===========================================================
RMAN-03002: failure of recover command at 08/29/2001 14:23:09
RMAN-06054: media recovery requesting unknown log: thread 1 scn
86945
The following excerpt is from the exciting book from Kamran
Agayev A. and Aman Sharma:
Oracle Backup & Recovery: Expert Secrets for Using RMAN and Data
Pump. See the book for the scripts and output results
associated with the steps listed below:
Scenario 1: Bob took a binary backup of the
controlfile. The next day he loses all controlfiles of the database
due to the media failure. As he has only the binary copy of the
controlfile, he restores it and recovers the database.
-
Take a
binary backup of the controlfile and delete all controlfiles.
Then shut down and start up the database ...
This results
in the following error:
ORA-00205: error in identifying control file, check alert log
for more info
- Copy the binary backup of controlfile
to the original controlfile's destination and mount the database
...
- If you try to open the database, you
get the message that you must use the resetlogs option. If you
use the resetlogs option, you are asked to perform a recovery.
If you try to recover the database, you are asked to use the
USING BACKUP CONTROLFILE clause. So you need to use the
recover database using backup controlfile command to tell
Oracle that you are trying to recover the database from the
binary copy of the controlfile ...
By using this command, Oracle asks you to provide the changes
made after the backup of the controlfile was taken. In this
scenario, you are prompted to provide the redo log file name that
contains the changes of the scn value
470859. To get the correct file which contains the changes made
after the specified scn, you need to
query both archived redo logs and online redo log files. In this
scenario, as you have not any archived redo log files generated,
query the v$log view: ...
To see more,
order your copy of the book now!
