6.0.1

EVC masks only those processor features that aect vMotion compatibility. Enabling EVC does not prevent
a virtual machine from taking advantage of faster processor speeds, increased numbers of CPU cores, or
hardware virtualization support that might be available on newer hosts.
EVC cannot prevent virtual machines from accessing hidden CPU features in all circumstances.
Applications that do not follow CPU vendor recommended methods of feature detection might behave
unexpectedly in an EVC environment. VMware EVC cannot be supported with ill-behaved applications that
do not follow the CPU vendor recommendations. For more information about creating well-behaved
applications, search the VMware Knowledge Base for the article Detecting and Using New Features in CPUs.
EVC Requirements for Hosts
To improve CPU compatibility between hosts that have varying CPU feature sets, you can hide some host
CPU features from the virtual machines by placing the host in an Enhanced vMotion Compatibility (EVC)
cluster. Hosts in an EVC cluster and hosts that you add to an existing EVC cluster must meet EVC
requirements.
n
Power o all virtual machines in the cluster that are running on hosts with a feature set greater than the
EVC mode that you intend to enable. You can also migrate these virtual machines out of the cluster.
n
All hosts in the cluster must meet the following requirements:
Requirements Description
Supported ESXi
version
ESXi 5.0 or later.
vCenter Server The host must be connected to a vCenter Server system.
CPUs A single vendor, either AMD or Intel.
Advanced CPU
features enabled
Enable these CPU features in the BIOS if they are available:
n
Hardware virtualization support (AMD-V or Intel VT)
n
AMD No eXecute(NX)
n
Intel eXecute Disable (XD)
N Hardware vendors sometimes disable particular CPU features in the BIOS by default. In
this case, you might have problems in enabling EVC, because the EVC compatibility checks
detect the absence of features that are expected to be present for a particular CPU. If you cannot
enable EVC on a system with a compatible processor, ensure that all features are enabled in the
BIOS.
Supported CPUs for
the EVC mode that
you want to enable
To check EVC support for a specic processor or server model, see the VMware Compatibility
Guide at hp://www.vmware.com/resources/compatibility/search.php.
Congured for
vMotion
See “Host Conguration for vMotion,” on page 121.
Create an EVC Cluster
Create an EVC cluster to ensure vMotion CPU compatibility between the hosts in the cluster.
To create an EVC cluster with minimal disruption to your existing infrastructure, create an empty EVC
cluster and move hosts into the cluster. To enable EVC on an existing cluster, see “Enable EVC on an
Existing Cluster,” on page 131.
Other cluster features such as vSphere DRS and vSphere HA are fully compatible with EVC. You can enable
these features when you create the cluster.
Prerequisites
Verify that the hosts you intend to add to the cluster meet the requirements listed in “EVC Requirements for
Hosts,” on page 130.
vCenter Server and Host Management
130 VMware, Inc.