As discussed in Chapter 11, Configuring and Managing vSphere 6.7, a vSphere cluster is a collection of ESXi hosts that share resources and a management interface. Some of the vSphere's features are available only on the cluster level and DRS is one of them. Once the DRS is enabled on the cluster, the capability to automatically balance loads across the ESXi hosts will be available. vSphere DRS provides two main functions:
- Executing the placement of the just-powered-on VM on a specific host in the cluster
- Periodically (every 5 minutes by default), DRS checks the load on the cluster, providing recommendations for migration or automatically migrate the VM (using vMotion) to get a balanced cluster
If you have a DRS-enabled cluster and one of the hosts is heavily loaded compared to other host members, you might notice DRS doesn't vMotion any running VM off the host...
