DynamoDB Point-in-Time Recovery (PITR) is a feature that provides the capability to restore your DynamoDB tables to any point in time within the last 35 days.
Recovery Point Objective (RPO) – RPO refers to the maximum acceptable amount of data loss measured in time. It represents the age of the data that must be recovered from backup storage for normal operations to resume after a disaster. Essentially, it is the maximum duration during which data might be lost due to a major incident.
Recovery Time Objective (RTO) – RTO is the maximum acceptable length of time that a service or application can be offline after a disaster before causing significant harm to the business. It measures the duration from the onset of an incident to the moment normal operations are restored.
Focus: RPO focuses on data and determines how much data loss is acceptable. In contrast, RTO focuses on time and determines how much downtime is acceptable.
Amazon DynamoDB offers two types of backups: point-in-time recovery (PITR) and on-demand backups.
PITR is used to recover your table to any point in time in a rolling 35 days window, On demand backups are designed for long-term archiving and retention, which is typically used to help customers meet compliance and regulatory requirements.
https://aws.amazon.com/blogs/database/part-2-set-up-scheduled-backups-for-amazon-dynamodb-using-aws-backup/
On-demand mode is a good option if any of the following are true:
– You create new tables with unknown workloads.
– You have unpredictable application traffic.
– You prefer the ease of paying for only what you use.
https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.ReadWriteCapacityMode.html#HowItWorks.OnDemand