Metadata store
Role of the metadata store
The metadata store is the database where RabbitMQ records everything except queue and stream messages:
- users and permissions in the internal authentication backend
- virtual hosts
- topology: exchanges, queues, streams, bindings
- runtime parameters
- policies
In a cluster, the metadata store replicates this information across all RabbitMQ nodes.
Khepri
RabbitMQ uses Khepri, a metadata store developed by the RabbitMQ team. Khepri is the only supported metadata store starting with RabbitMQ 4.3. It replaced Mnesia, the metadata store used by earlier releases.
Like quorum queues and streams, Khepri uses the Raft consensus algorithm. A majority of cluster nodes must be available for metadata updates and cluster membership changes.
The following guides cover clustering, everyday operations, and failure recovery with Khepri.