Datastore Cluster is a collection of datastores with shared storage and management, Once configured you can enable storage DRS to manage and balanced the load across all datastores in the cluster similar to DRS.
To create a Datastore cluster go to Home “Datastores and Datastores Clusters”
Right Click on the Datacentre and Click New Datastore Cluster
Name the Cluster and Select to Enable Storage DRS.
Set SDRS automation level
Select Datastores that will form the Cluster.
Review and Click Finish