Understanding Amazon DynamoDB On-Demand Backups and Billing

Amazon DynamoDB provides a powerful and flexible NoSQL database service, allowing users to scale effortlessly and handle diverse workloads. One crucial feature that DynamoDB offers is on-demand backups, which ensure data durability and recovery options for users. However, the billing model associated with on-demand backups can sometimes be a source of confusion, particularly due to its unique characteristics.

On-Demand Backups Overview

On-demand backups in DynamoDB allow users to create instant backups of their tables, providing a safety net in case of accidental data loss or corruption. These backups are essential for maintaining data integrity and meeting regulatory compliance requirements.

Billing Peculiarities

The billing for on-demand backups is based on the TimedBackupStorage-ByteHrs metric, and it's priced per GB-month. Here's where the confusion often arises: DynamoDB recognizes the full month's revenue for all existing stored backups on the first day of the month. This billing behavior results in a notable spike in charges on the first of each month.

On day 1 of the month, the daily charge reflects the cost of retaining backups for the entire month. This can catch users off guard, especially if they are not aware of this billing model. It's essential to understand that the apparent surge in charges on the first day of the month is a result of DynamoDB accounting for the full month's backup storage.

Prorated Credits for Deletion

If you decide to delete your on-demand backup before the end of the month, DynamoDB provides prorated credits based on the rate of on-demand backups. This means that your month-end bill will accurately reflect your on-demand backup usage, considering the storage for the actual number of days the backups were retained.

This prorated credit system ensures that you are not overcharged if you choose to delete your backups during the billing cycle. It aligns the charges with the actual usage, offering flexibility for users managing their backup strategies.

Conclusion

Understanding the billing intricacies of DynamoDB on-demand backups is crucial for effectively managing costs and avoiding unexpected spikes. By being aware of the monthly billing cycle and taking advantage of prorated credits for deletions, users can optimize their DynamoDB usage while ensuring the safety and resilience of their data.