Recover Database from SCRATCH

Overview: This Example shows how an Oracle Database can be recovered or reconstructed by using only the RMAN backup files (from Disks) in case of complete server crash. It is essential for every DBA to plan and test his Backup - Recovery strategy in advance to anticipate future difficulties. 

If Your database is running in No Archive log mode and you have Daily/ Weekly RMAN backup configured. One day, your server crashed and you lose one of the disks or all the disks and you have no other option but to restore the whole database backup to point of last valid backup.

Recommendation:If you have your database is in Archivelog then you can recover up to the point of failure time. So it is recommended always keep your database is in Archivelog and properly take the backup of archive before deleting the physical archivelog

To test the validity of a RMAN backup a full restore and recovery of databases can be performed from scratch on the same or another server using RMAN backups which have been restored from the disk backups
This Example illustrate the procedure by detailing the steps required to restore the backup of a production database on the same server with same location or different server with same location
Steps:
§        Restore the spfile from the autobackup
§        Restore the controlfile from the autobackup
§        Restore database
§        Recover the database
§        Open the database with resetlogs

Note: Use the command RECOVER DATABASE NOREDO; if you donot want to apply redolog or if your database in NOARCHIVELOG mode. In fact there is no need to recover the database if you have taken consistent (shutdown mode) backup.

Full database backup
Before start the actual recovery process for the test purpose take a full backup of your database for precaution.
 

Restore the SPFILE
Here i used the pfile because database is already started with spfile you need to use "startup force nomount"
 

Restore the Controlfile
 

Restore Database

 

Recover Database
 

At this stage if you find the following type of error then do not be panic. You just need to open the database using Resetlogsunable to find archive logarchive log thread=1 sequence=33RMAN-00571: ========================================RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS RMAN-00571: ========================================RMAN-03002: failure of recover command at 05/06/2012 14:45:21RMAN-06054: media recovery requesting unknown log: thread 1 seq 33 lowscn27801294Alternatively you can use Incomplete recovery (Cancel based) from the SQL prompt and open the database using Resetlogs option. SQL>Recover database until cancel;-or-SQL>Recover database until cancel using backup controlfile;



Open the Database