This page introduces the shard cluster system architecture of DDS to help you better understand DDS.
The cluster system architecture consists of three types of roles: Mongos, Shard, and ConfigServer. You can freely choose the number and specifications of Mongos and Shards to form a cluster that meets your current business capacity needs.
l Mongos Role: Responsible for routing read and write requests and distributing them to Shard. The default is at least two Mongos and supports up to 16 Mongos.
l Shard Role: Responsible for data read/write processing and data storage. It is a three-node replica set architecture, and the Primary nodes in the Shard failover automatically. The default is at least two Shards and supports up to 16 Shards.
l ConfigServer Role: Responsible for cluster metadata storage. It is a three-node replica set architecture, and the Primary nodes in the ConfigServer failover automatically. The number is not optional, fixed at One.
Cluster System Architecture is as follows：
