6.7

Table Of Contents
Creating a DRS Cluster 11
A cluster is a collection of ESXi hosts and associated virtual machines with shared resources and a
shared management interface. Before you can obtain the benefits of cluster-level resource management
you must create a cluster and enable DRS.
Depending on whether or not Enhanced vMotion Compatibility (EVC) is enabled, DRS behaves differently
when you use vSphere Fault Tolerance (vSphere FT) virtual machines in your cluster.
Table 111. DRS Behavior with vSphere FT Virtual Machines and EVC
EVC DRS (Load Balancing) DRS (Initial Placement)
Enabled Enabled (Primary and Secondary VMs) Enabled (Primary and Secondary VMs)
Disabled Disabled (Primary and Secondary VMs) Disabled (Primary VMs)
Fully Automated (Secondary VMs)
This chapter includes the following topics:
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Admission Control and Initial Placement
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Virtual Machine Migration
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DRS Cluster Requirements
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Configuring DRS with Virtual Flash
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Create a Cluster
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Edit Cluster Settings
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Set a Custom Automation Level for a Virtual Machine
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Disable DRS
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Restore a Resource Pool Tree
Admission Control and Initial Placement
When you attempt to power on a single virtual machine or a group of virtual machines in a DRS-enabled
cluster, vCenter Server performs admission control. It checks that there are enough resources in the
cluster to support the virtual machine(s).
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