AWS Backup for RDS

Hello.

Do the tag values ​​and keys set on the RDS instance match the resource selection settings set in AWS Backup?
Tag values ​​are case sensitive and must match exactly.

Hi,

Do you have resource type parametrized in your config in addition to tag? In that case, resource type takes over:

see https://docs.aws.amazon.com/aws-backup/latest/devguide/assigning-resources.html

If both a resource type and tags are specified in a resource assignment, the resource type 
specified in the backup plan takes priority over the tag condition. Service opt-in settings
 are disregarded in this situation.

Best,

Didier

As a last resort, if Didier's suggestion does not pan out, I'd go back to Riku's suggestion about tag values. I have experienced situations where the tag values look EXACTLY the same, but one somehow has a space or some other thing in it that the display doesn't show. You can always manually re-type the tag value for the RDS that did not backup just to eliminate this possibility. Best.

Thanks all. With some testing, the problem is likely too close to the automated backup window configured in RDS instance.