Cluster
Each DDS cluster consists of a config node, and multiple dds mongos and shard nodes. The following diagram shows the node relationships.
Figure 1 Diagram of node relationships
dds mongos
A dds mongos is a router for reading and writing data, providing a unified interface for accessing DB instances.
- Each DB instance has 2 to 32 dds mongos nodes. You can specify the quantity.
- A dds mongos reads configuration settings from the config node and allocates read and write requests to shard nodes. You can connect to a dds mongos directly.
config
A config stores configuration settings for DB instances and consists of one replica set.
You cannot connect to a config node directly.
shard
Shards are used to store user data.
- Each Community Edition instance has 2 to 32 shard nodes. You can specify the quantity.
- Each shard node is deployed as a replica set to ensure data redundancy and high reliability.
- You cannot connect to a shard node directly.
Parent topic: Basic Concepts
- dds mongos
- config
- shard