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• State Management: Mirror partition states and control records are stored in __mirror_state internal topic. The coordinator loads these metadata on startup and partition leadership changes.
• Partition Assignment: Mirror partitions are distributed evenly to coordinators across all brokers and allows for horizontal scaling. The number of coordinator partitions is configurable via mirror.topic.num.partitions.
• Leader Election: When a broker becomes the leader for a __mirror_state partition, it loads the mirror metadata for all mirrors assigned to that partition and begins coordinating those mirrors. On resignation, it clears its in-memory state to avoid stale metadata.
• Metadata Refresh Scheduling: The coordinator schedules periodic metadata refresh operations by invoking a metadata manager every 30 seconds by default. This ensures that topology changes, configuration updates , and offset commits in the source cluster are continuously propagated to the destination cluster.  The The refresh interval is configurable via mirror.metadata.refresh.interval.ms.
• State Transitions: The coordinator manages asynchronous state transitions for mirror partitions. Each partition is an independent replication unit with its own state. When the coordinator is the leader for a mirror partition, it writes the state updates directly to __mirror_state topic, otherwise it reads and writes the state via new internal RPCs, enabling distributed coordination across the cluster.

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