What High-Reliability Mechanisms Does DDM Provide?¶
Protection of Data Integrity¶
DDM instance faults do not affect data integrity.
Service data is stored in shards of data nodes, but not on DDM.
Configuration information of schemas and logical tables is stored in DDM databases. Primary and standby DDM databases are highly available.
High Availability¶
DDM is deployed using multiple stateless nodes in cluster mode and provides services through the IP address bound to your load balancer.
If one DDM node becomes faulty, an error is returned for connections established on the node, without affecting the DDM cluster. The faulty node is generally deleted from the cluster within 5 seconds.
If a data node becomes faulty, services can be restored within 30 seconds after the data node is recovered.