Impact on virtual machines when vSphere DRS is set to "Fully Automated"

Products

• VMware vSphere ESXi
• VMware vCenter Server

Issue/Introduction

• The cluster's vSphere DRS setting is "On" and "Manual."
• What impact will changing this setting to "On" or "Fully Automated" have on virtual machines?
• Will there be a momentary interruption in virtual machine operation when DRS is triggered?

Environment

vSphere 7.0

vSphere 8.0

vSphere 9.0

Resolution

• By changing the vSphere DRS setting to "On" or "Fully Automated," virtual machines on the cluster will be automatically migrated to other hosts based on resource usage.
• When a virtual machine is started, it will be automatically placed on the ESXi host with the best resource usage.
• DRS migration generally does not cause any interruptions to the virtual machine, however, interruptions may occur depending on the load on the virtual machine.
• For an overview of vSphere DRS, see KB 391137.

VMware DRS Overview: Optimizing Resource Allocation in vSphere Cluster
https://knowledge.broadcom.com/external/article/391137/

Additional Information

References: 

Admission Control and Initial Placement

Virtual Machine Migration

Edit Cluster Settings

Virtual Machine Conditions and Limitations for vSphere vMotion

VMware DRS Overview: Optimizing Resource Allocation in vSphere Cluster