Automated backups occur daily during the preferred backup window. If the backup requires more time than allotted to the backup window, the backup continues after the window ends, until it finishes. The backup window can't overlap with the weekly maintenance window for the DB instance.
During the automatic backup window, storage I/O might be suspended briefly while the backup process initializes (typically under a few seconds). You might experience elevated latencies for a few minutes during backups for Multi-AZ deployments.
The backup window is normally selected at random from an eight-hour block of time per Region by the Amazon RDS control plane underlying Neptune. The time blocks for each Region from which the default backups windows are assigned is documented in the Backup Window section of the Amazon RDS User Guide.
