A cluster is a collection of ESXi hosts with shared CPU and memory resources. DRS provides the functionalities of initial placement and automated load balancing based on the CPU and memory usage. The DRS rules can be created to specify affinity or anti-affinity in order to keep virtual machines together or apart. vSphere HA is another cluster feature. vSphere HA continuously monitors the ESXi hosts in the cluster, and in the event of a failure, the virtual machines are restarted on an alternate ESXi host. Host network isolation occurs when an ESXi host is still up and running but no longer exchanges traffic from the HA agents on the management network.

A datastore cluster is a collection of datastores on which Storage DRS may be enabled. Storage DRS balances virtual machine files across the datastore cluster based on the datastore use and the I/O latency. The Storage DRS rules can be created to control the placement of virtual disks on a datastore within the datastore cluster.

The...