The point to be considered when writing a RMAN Backup Scripts are as follows:
1. After Each and Every Backup must read Backup log file carefully.
2. Put “Set Echo ON” at the beginning of RMAN script then RMAN will reflect all command in log files.
3. Use “Show all” Command in RMAN script, it will allow you to understand behaviors of RMAN Backup.
4. Use the command to find the Total execution time of script in the RMAN backup script that will help you to manage the expected time of next backup.
5. Do not overwrite the Backup log files. The log file is good alternative solution of information in case the Rman Catalog is not available. Use the command to generate log file sequence or some alternative solution.
6. Do not use Crosscheck command with RMAN backup script. By using it wrong place in your backup script will make recovery impossible. Handle it manually as required for precaution.
7. Always Backup controlfile as the last step in your backup script. After that do not use Crosscheck or Obsolete command.
8. Do not rely on one backup only. You should always have second option for potential recovery. Possibly keep one set of copy to another server.
9. Use Connect Target with RMAN Backup script rather than passing it as an RMAN Executable Parameter.
10. Use “resync catalog” command to synchronize the Catalog with the backup as a last step of the RMAN script.
11. Do not rely on the RMAN stored configuration setting always put the configuration with the Backup script.
12. Use “Report Need Backup” command to verify your backup up to the mark of recovery process.
13. Use “Report unrecoverable” command with the backup
script. This will indicate which database files need to be backed up to
meet a configured or specified retention policy
Example of writing a RMAN backup scripts.
Backup a complete database:
(If the target database is in archive mode, this can be done while the database is open)
RMAN>
run {
# backup complete database to disk
allocate channel c1 type disk;
backup full
tag full_db
format '/usr1/ora817/test/rman/db_d.dmp'
(database);
release channel c1;
}
You can create a script and use it multiple times, so each time you don't need to type the above script. Just make sure to drop the old backup files.
RMAN>
create script full_db_backup {
allocate channel c1 type disk;
backup full database
format '/usr1/ora817/test/rman/db_%d.dmp';
release channel c1;
}
This is how you run the script:
RMAN>
run { execute script full_backup ;}
Archive logs too can be backed up along with the database in one script:
RMAN>
create script full_db_arc_backup {
allocate channel c1 type disk;
backup full database
format '/usr1/ora817/test/rman/db_%d.dmp';
release channel c1;
allocate channel c2 type disk format '/usr1/ora817/test/rman/arc_%d.dmp';
backup (archivelog all delete input);
release channel c2;
}
- '%d' puts database name in the backup file name.
- 'all delete input' in above script deletes all the archive logs once the backup is
complete, thus frees up the space.
RMAN>
run { execute script full_db_arc_backup ;}
