Doris 3.x/4.x: recommended cross-cluster replication solution and CCR maintenance status

[2ez4Zack]

Hello Doris community,

We operate two independent Doris clusters and need long-running, one-way replication at the database or table level, covering both the initial full synchronization and continuous real-time incremental synchronization. We currently use ccr-syncer with Doris 2.1.8.3 on both the source and destination clusters. Our questions about Doris 3.x/4.x concern a possible future upgrade.

We noticed that the CCR documentation was removed from the 3.x and 4.x documentation. Could the maintainers clarify the following points to help with production planning and future upgrades?

1. Is CCR still a recommended cross-cluster replication solution for Doris 3.x and 4.x? Does the documentation removal indicate deprecation or the end of maintenance, or was there another reason?
2. If CCR remains supported, could you provide a compatibility matrix for the source Doris version, destination Doris version, and Syncer version, including the supported scope for storage-compute coupled and decoupled architectures? Which Syncer branch and release are currently maintained and recommended? Are there any publicly documented production deployments?
3. If CCR is no longer recommended, what is the recommended alternative for continuous real-time Doris-to-Doris replication? Are there any replacement-solution documents or migration guides? For Doris 3.x and 4.x, can the Flink Doris Connector directly read incremental changes from Doris to implement this use case?
4. For the recommended approach, is there production guidance covering the support boundaries for UPDATE, DELETE, and DDL, as well as initial full-sync throttling, resource controls, and failure recovery?

Our goal is to choose a solution with a clear support scope and a sustainable maintenance path. Links to relevant documentation, release notes, or a roadmap would be greatly appreciated. Thank you!

Current environment:

• Source Doris version: 2.1.8.3
• Destination Doris version: 2.1.8.3
• CCR Syncer version (reported by /version): 2.1.10-rc08:0a9434c

References reviewed:

• CCR documentation removal PR #4018
• CCR tracking issue #66265
• Related Doris-to-Doris CDC discussion #61252