As the DB instance deployment time and services increase, the database running performance and storage will gradually reach the bottleneck. For GaussDB(openGauss), you can add nodes to improve the DB instance performance and storage capability.
The number of CNs of a DB instance must be less than or equal to twice the number of shards.
A shard contains three DN replicas by default. Therefore, three DN replicas are added each time a shard is added.