RDS Generating Automated backups thrice daily

Hi Som,

Automated backup (system snapshots) occurs during a daily user-configurable 30 minute period known as the backup window. Please refer to the link[1] for more details.

But when you create a read replica of an RDS instance, Amazon RDS takes a snapshot of the source instance and creates a read-only instance from the snapshot[2]. Since this snapshot is also taken up by RDS, its mentioned/shows in the Snapshots--> System snapshots tab only.

So if you are seeing 3 system snapshots being created for the RDS instance just check if you have triggered creating a Read Replica before the system snapshot is triggered outside of the window or not.

Rest it might also depend on the engine and the events triggered on the RDS instance around that time as well. Like SQL server RDS might have some emergent snapshot as mentioned in the link[3].

References:-

[1] Amazon RDS Backup and Restore:- https://aws.amazon.com/rds/features/backup/

[2] Working with DB instance read replicas - How read replicas work - https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_ReadRepl.html#USER_ReadRepl.Overview.how-it-works

[3] Emergent Snapshot Request: Databases found to still be awaiting snapshot.:- https://repost.aws/knowledge-center/rds-sql-server-emergent-snapshot-backup