A cluster with three data nodes of 320 GB each has a total capacity of 960 GB. When 1 GB data is stored, GaussDB(DWS) stores 1 GB data on two nodes due to duplication, a security mechanism, thereby occupying a total of 2 GB space. As a result, more than 2 GB space is occupied if metadata and indexes are calculated. Therefore, a three-node cluster with a total capacity of 960 GB can store 480 GB data. This mechanism ensures data security.
When you create nodes on the console, you are billed by the available capacity of a node. For example, the actual space of dws.m3.xlarge is 320 GB and the available space displayed is 160 GB, the space you will be billed for.