In our example above, any backup that we have in our system (both on RMAN catalog, and as physical RMAN backup files at the filesystem level) that is older than 4 days is considered obsolete. Please keep in mind that sometimes it might not be just 4 days. It depends on whether a full-backup is available within the last 4 days. If you don’t have a full backup in the last 4 days, then what RMAN considers as obsolete will be even longer than that. i.e Until the last full backup.
Obsolete backups are those that are not required to satisfy RMAN requirement of what is specified in the retention policy to recover the database from the backup.
The following three things will happen when you perform “DELETE OBSOLETE” from RMAN prompt:
2. View Backups Before Delete Obsolete
In the following example, I see that there are lot of backup that I have on the system that are way older than what I need to satisfy my recovery requirement. i.e I have backups starting from 6th June until 26th Sep (several months).
RMAN> LIST BACKUP SUMMARY;
3. Perform RMAN CrossCheck
Before we start executing the delete obsolete command, it is always recommended to do a crosscheck of the backup as shown below.
crosscheck backup command will check for the records in the RMAN repository to make sure they are accurate. If there is an record in the RMAN catalog that is not available on the physical filesystem, it will make that entry with appropriate status.
RMAN> CROSSCHECK BACKUP;
4. Delete Obsolete RMAN backup
Once the crosscheck is done, it is time to delete the old obsolete backup using the DELETE OBSOLETE command as shown below.
RMAN> DELETE OBSOLETE;
5. Other Delete Obsolete Options
If you are writing a shell script that will automatically do this for you on an on-going basis, you don’t want to manually say “YES” to delete obsolete command as shown above.
Instead, you can ignore the prompt and automatically delete all obsolete backups as shown below.
RMAN> DELETE NOPROMPT OBSOLETE;
Also, if you want to delete obsolete backup based on your own recovery window criteria (instead of what is configured in RMAN when you do “show all”), you can specify it as shown below. The following will delete old backups based on recovery window of 10 days.
RMAN> DELETE OBSOLETE RECOVERY WINDOW OF 10 DAYS;
6. View Backups After Delete Obsolete
Finally, if you do the list backup summary, you’ll notice that this has only the backups that are required to satisfy the recovery criteria. All other backups are deleted.
RMAN> LIST BACKUP SUMMARY;
II. Delete Expired Backup
1. What is an Expired Backup?
When you have an entry in the RMAN repository for a backup, but there are no corresponding physical rman backup files at the filesystem level, that is considered as expired entry.
But, you need to execute the crosscheck command, which will go through all the records in the RMAN catalog, and mark any expired records appropriately.
RMAN> CROSSCHECK BACKUP;
3. View Backups Before Delete Expired
As you see from the output below, there are several records in the RMAN catalog that are marked as EXPIRED.
RMAN> LIST BACKUP SUMMARY;
4. Delete Expired RMAN Catalog Entries
The following will delete all the records that are in RMAN catalog which are marked as EXPIRED. In other words, this deletes the expired records that don’t have the corresponding physical RMAN backup file in the filesystem.
RMAN> DELETE EXPIRED BACKUP;
5. View Backups After Delete Expired
After deleting the expired entries, view the catalog to make sure it contains only the active available RMAN backup records.
RMAN> LIST BACKUP SUMMARY;
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