When you add a host to a DRS cluster, the host’s resources become part of the cluster’s resources. In addition to this aggregation of resources, with a DRS cluster you can support cluster-wide resource pools and enforce cluster-level resource allocation policies.

About this task

The following cluster-level resource management capabilities are also available.

Load Balancing

The distribution and usage of CPU and memory resources for all hosts and virtual machines in the cluster are continuously monitored. DRS compares these metrics to an ideal resource utilization given the attributes of the cluster’s resource pools and virtual machines, the current demand, and the imbalance target. It then performs (or recommends) virtual machine migrations accordingly. See Virtual Machine Migration. When you first power on a virtual machine in the cluster, DRS attempts to maintain proper load balancing by either placing the virtual machine on an appropriate host or making a recommendation. See Admission Control and Initial Placement.

Power management

When the vSphere Distributed Power Management (DPM) feature is enabled, DRS compares cluster- and host-level capacity to the demands of the cluster’s virtual machines, including recent historical demand. It places (or recommends placing) hosts in standby power mode if sufficient excess capacity is found or powering on hosts if capacity is needed. Depending on the resulting host power state recommendations, virtual machines might need to be migrated to and from the hosts as well. See Managing Power Resources.

Affinity Rules

You can control the placement of virtual machines on hosts within a cluster, by assigning affinity rules. See Using DRS Affinity Rules.


You can create a cluster without a special license, but you must have a license to enable a cluster for vSphere DRS (or vSphere HA).


  1. Right-click a data center in the vSphere Web Client and select New Cluster.
  2. Name the cluster in the Name text box.

    This name appears in the vSphere Web Client navigator.

  3. Select the DRS Turn ON check box.
  4. Select a default automation level for DRS.

    Automation Level



    • Initial placement: Recommended host(s) is displayed.

    • Migration: Recommendation is displayed.

    Partially Automated

    • Initial placement: Automatic.

    • Migration: Recommendation is displayed.

    Fully Automated

    • Initial placement: Automatic.

    • Migration: Recommendation is executed automatically.

  5. Set the migration threshold for DRS.
  6. (Optional) Select the vSphere HA Turn ON check box to enable vSphere HA.

    vSphere HA allows you to:

    • Enable host monitoring.

    • Enable admission control.

    • Specify the type of policy that admission control should enforce.

    • Adjust the monitoring sensitivity of virtual machine monitoring.

  7. If appropriate, enable Enhanced vMotion Compatibility (EVC) and select the mode it should operate in.
  8. Click OK to complete cluster creation.


A new cluster does not include any hosts or virtual machines.

To add hosts and virtual machines to the cluster see Adding Hosts to a Cluster.