VMware KB 1007006: Implications of enabling or disabling VMware HA strict admission control when using DRS and VMware DPM

VMware KB: Implications of enabling or disabling VMware HA strict admission control when using DRS and VMware DPM.


EVC (Enhanced vMotion)


  • 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


  • 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

Report Errors



1. Click Submit error report to send the error report.
The Submit Error Report window displays details about the specific error.
2. (Optional) Click the printer icon to print the error log report.
3. (Optional) Click the disk icon to save the error log report.
The error log report can be saved as an HTML file. If you are working offlline, this allows you to use the HTML file to submit the error report to VMware at a later time.
4. Click Submit.

The data that appears is sent to VMware in XML format to be analyzed. If found, a relevant VMware Knowledge Base article displays.