Replication automatically copies objects between buckets. Versioning must be enabled in both source and destination.
- Cross-Region Replication (CRR): Replicates to a different AWS region.
- Same-Region Replication (SRR): Replicates within the same region.
- Buckets can be in the same or different AWS accounts.
- Replication is asynchronous and requires appropriate IAM permissions for S3.
Use cases:
- CRR: Compliance, disaster recovery, or reduced latency in other regions.
- SRR: Log aggregation, syncing between environments (e.g., prod → test).
Replication – Key Notes
- Replication applies only to new objects after it is enabled.
- Existing objects can be replicated using S3 Batch Replication.
- You can choose to replicate delete markers; deletions with a Version ID are not replicated to avoid malicious deletes.
- Replication is not chained — a bucket replicated to another will not forward replicated objects further.