A region is a geographical area where a physical Cloud Data Warehouse server is located. Select a Tencent Cloud region with caution as you cannot change it after service purchase and networks are completely isolated between regions. For a lower access latency and higher read and write speeds, we recommend you select a region closest to your users.
An availability zone (AZ) is a physical IDC with isolated resources within a region.
A Cloud Data Warehouse cluster is a distributed cluster of multiple ClickHouse nodes, each of which may have one or two replicas depending on the specifications you purchase. A cluster may contain one or more shards.
Cloud Data Warehouse stores massive amounts of data on multiple nodes, each of which only stores and processes a part of the data. When there is one replica, a shard corresponds to a node; when there are two replicas, a shard corresponds to two nodes.
A replica is used to guarantee data security and service availability in case of exceptions. Cloud Data Warehouse stores data on two nodes to generate two replicas.
In HA mode, each shard has two replicas to ensure the cluster availability in case one of them fails.