Replication is not backup
MirrorMaker 2 is excellent at what it does: real-time replication between clusters. But it faithfully replicates corrupted data, accidental deletes, and bad deploys too. Here is how the two approaches differ — and why mature Kafka estates usually run both.
Two different jobs
MirrorMaker 2 continuously copies topics from a source cluster to a target cluster over Kafka Connect. It is the right tool for active-active topologies, geo-distribution, and near-zero RPO failover.
OSO Kafka Backup takes point-in-time backups of topic data, consumer group offsets, and cluster metadata to object storage (S3, Azure Blob, GCS) or local disk, and restores any of it — to the same cluster or a different one — with millisecond precision. See the disaster recovery use cases for the failure scenarios each covers.
The critical difference: when a producer bug poisons a topic, MirrorMaker 2 ships the poison to your standby cluster within milliseconds. A backup gives you the state of the topic from before the incident.
| Feature | OSO Kafka Backup | MirrorMaker 2 |
|---|---|---|
| Purpose | Backup / restore | Real-time replication |
| Point-in-time recovery | Yes | No |
| Protects against bad data / deletes | Yes | No |
| Storage backends | S3, Azure, GCS, local | Kafka only |
| Offset preservation | Built-in | Requires configuration |
| Network requirement | One-time transfer | Continuous connection |
| Compression | Zstd, LZ4 | Kafka default |
| Infrastructure cost | Object storage | A second full cluster |
| Recovery time (RTO) | Minutes–hours | Instant (already replicated) |
| Data loss window (RPO) | Since last backup | Near-zero |
When to choose which
Choose OSO Kafka Backup when you need point-in-time recovery, your clusters cannot hold a continuous connection, compliance requires immutable copies outside the cluster, or a second full Kafka cluster is not in the budget.
Choose MirrorMaker 2 when you need near-zero RPO failover, active-active topologies, or real-time geo-distribution.
Run both when you are protecting production: MirrorMaker 2 for availability, backups for recoverability. Replication keeps you online through infrastructure failure; backups get your data back after logical corruption. The full feature comparison covers tiered storage and custom scripts as well.
Frequently asked questions
Does MirrorMaker 2 protect against accidental topic deletion?
No. MirrorMaker 2 replicates the state of the source cluster, so deletions and corrupted records propagate to the target. Point-in-time backups let you restore the topic to the moment before the deletion.
Can OSO Kafka Backup preserve consumer group offsets like MirrorMaker 2?
Yes. Offset preservation is built in: backups capture consumer group offsets alongside topic data, and restores keep them consistent with the restored records, so consumers resume from the right position.
Is OSO Kafka Backup cheaper to run than MirrorMaker 2?
Usually. MirrorMaker 2 needs a second, continuously running Kafka cluster plus Connect infrastructure. Backups need object storage, which is priced per GB stored — and Zstd or LZ4 compression reduces that footprint further.
Can I use OSO Kafka Backup and MirrorMaker 2 together?
Yes, and many teams should. MirrorMaker 2 provides low-RPO availability across clusters, while scheduled backups provide point-in-time recoverability from logical errors. They protect against different failure modes.
Ready to protect your Kafka data?
Take your first backup in minutes with the open source CLI, or talk to us about Enterprise features like encryption, RBAC, and audit logging.