This article explains how Amazon Aurora backup architecture works, how it differs from RDS, and strategies to optimize backup storage costs.

• Aurora uses continuous backup at storage layer with no performance impact on database
• Automated backups free up to 100% cluster volume; charges apply beyond that threshold
• Manual snapshots are full backups sized at cluster volume at creation time
• CloudWatch metrics track BackupRetentionPeriodStorageUsed, SnapshotStorageUsed, and TotalBackupStorageBilled
• Backup costs depend on retention period, data change rate, and snapshot management practices
• DELETE operations free space but don't shrink volume; DROP TABLE triggers dynamic resizing
• Update-heavy workloads retain previous page versions, temporarily growing base image beyond table size
• Global databases with headless clusters offer cost-effective multi-region disaster recovery
• Cross-region snapshot copies incur full snapshot costs per copy plus data transfer fees
• Optimize by right-sizing retention periods, deleting unnecessary snapshots, and monitoring change rates

Aurora's distributed storage architecture enables efficient, zero-impact backups with point-in-time recovery. Understanding workload patterns and retention needs helps minimize backup storage costs.