vSphere Distributed Resource Scheduler (DRS) is a feature of vCenter that pools resources from a given cluster of hosts. It then efficiently organizes the running virtual machines across the ESXi to ensure optimal resource utilization at a cluster level. Furthermore, it also aids in initial placement of the virtual machine on the best-suited host. While the virtual machines are optimally placed, an administrator can impose certain rules and conditions to meet availability and application requirements.
DRS also enables a higher degree of automation for the purposes of host maintenance, upgrades/updates, and also to modify (increase/decrease) cluster capacity non-disruptively.
In addition to load balancing, DRS can also be extended to power management in conjunction with Distributed Power Management (DPM).
