Looking @ VMware vSphere DRS and HA Together

(1) VMware vSphere DRS (Distributed Resource Scheduler) cluster is a group of ESXi hosts and VMs that split CPU and memory resources for the whole VMware data-centers. After an ESXi failure a VM is powered on in a different host\cluster, then DRS try to maintain proper load balancing by either placing the VM on a right host or making a recommendation.

(2) VMware vSphere HA (High Availability) cluster is a utility included in VMware's vSphere that can restart failed virtual machines (VMs) on a replacement host. ESXi host failure – if an ESXi host fails, VMs that were running on that host are automatically restarted on another ESXi hosts.

ITSA Support and Virtualization in Cloud Computing.