In this tutorial, we are going to discuss the backup strategy concerning administrator-level a.k.a. user-managed backups. I have included most of the steps with the appropriate screenshots which will be useful to understand the concept clearly.
There are 2 types of user-managed backup,
- The cold backup (consistent backup) database is offline
- The hot backup (inconsistent backup) database is online
Cold backup
- Create a directory using below command,
Mkdir –p /u01/app/oracle/coldbkup
- Shutdown the database as bcoz, its cold backup(consistency backup)
- Copy all the datafiles, logfiles and controlfiles using cp command,
Possible cases dealing with corruption of database
- Missing user datafile
Now, we are going to simulate the disaster like deleting any data file,
When starting the database, it throws below error,
To fix this error,
Shutdown the database completely,
Copy the deleted file to the database location,
Then open up the database,
- Missing control file
As a cold backup strategy, if any files missing, we should shut down the database before the start of restoration
To fix this error,
Shut down the database,
Use shut abort as control file is missing,
Copy the control file from the backup location,
While trying to mount the database, we are getting inconsistency,
Then copy the higher version cfile to smaller one,
Now, when trying to open the database, needs media recovery,
Then, we are checking the checkpoint and fuzziness of the datafile,
If the control file is deleted, we have to copy all the datafiles along with the control file to retain the consistency. Otherwise there will be mismatched timestamp always.
Now check the fuzzy and checkpoint then open the database,
Hot backup
Note: log mode should be archive log as because the database is running.
Check the archive log mode in mount state as like below,
Begin the backup by enabling that command,
Copy the data files, log files and control file to the different location,
Whatever transactions happened, at the time of the backup will be archived as,
Complete the backup with the above command.