EVC (Enhanced vMotion)


Basics

  • Enhanced vMotion leverages AMD’s AMD-V Extended migration and Intel’s flex migration.
  • EVC ensures all hosts in the cluster present same features to all Virtual Machine even if actual CPU’s on the host differs.
  • EVC masks only those features which affects vMotion compatibility.
  • EVC can be configured from cluster setting.
  • Enabling EVC does not prevent a Virtual Machine from using hardware virtualization features available on new processors
  • EVC cannot prevent application from accessing hidden features in all circumstances.
  • VMware EVC cannot be supported on ill-behaved application who does not follow CPU vendor recommended guidelines

Pre-requisites

  • Power off Virtual Machines of the Hosts which has greater feature set than EVC mode you intend to enable.

e.g.Cluster has two nodes each of Intel Xeon core 2 and Intel Xeon 45nm Core 2 . So in this case you intend to enable Intel Core 2 EVC mode, then Virtual Machine running on Intel Xeon 45nm Core 2 must be powered off or moved out of cluster before enabling EVC

  • All hosts in the cluster must be either Intel or AMD but not mixed
  • All hosts in the cluster must have advanced CPU features like Hardware virtualization Intel-VT/AMD-V must be enabled in the BIOS

EVC compatibility checks detects the absence of features which it expects it to be present for a particular CPU.

  • All CPU’s in the cluster must have supported EVC mode you want to enable
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