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The vCenter Server AMD Opteron Gen. 3 (no 3DNow!) EVC mode masks the 3DNow! instructions from
virtual machines. You can apply this EVC mode to EVC clusters containing only AMD Opteron Generation
3 hosts. Applying this mode allows the clusters to maintain vMotion compatibility with AMD Opteron hosts
that do not have 3DNow! instructions. Clusters containing AMD Opteron Generation 1 or AMD Opteron
Generation 2 hosts cannot be made vMotion-compatible with hosts that do not have 3DNow! instructions.
Prerequisites
Ensure that the cluster contains only hosts with AMD Opteron Generation 3 or newer processors.
Procedure
u
Enable the AMD Opteron Gen. 3 (no 3DNow!) EVC mode for your EVC cluster.
The steps to enable the EVC mode differ depending on whether you are creating a cluster or enabling
the mode on an existing cluster, and on whether the existing cluster contains powered-on virtual
machines.
Option Description
Creating a cluster In the New Cluster wizard, enable EVC for AMD hosts and select the AMD
Opteron Gen. 3 (no 3DNow!) EVC mode.
Editing a cluster without powered-on
virtual machines
In the Cluster Settings dialog box, edit the VMware EVC settings and select the
AMD Opteron Gen. 3 (no 3DNow!) EVC mode.
Editing a cluster with powered-on
virtual machines
The AMD Opteron Gen. 3 (no 3DNow!) EVC mode cannot be enabled while
there are powered-on virtual machines in the cluster.
a Power-off any running virtual machines in the cluster, or migrate them out of
the cluster using vMotion.
Migrating the virtual machines out of the cluster with vMotion allows you to
delay powering off the virtual machines until a more convenient time.
b In the Cluster Settings dialog box, edit the VMware EVC settings and select
the AMD Opteron Gen. 3 (no 3DNow!) EVC mode.
c If you migrated virtual machines out of the cluster, power them off and cold
migrate them back into the cluster.
d Power on the virtual machines.
You can now add hosts with AMD processors without 3DNow! instructions to the cluster and preserve
vMotion compatibility between the new hosts and the existing hosts in the cluster.
CPU Compatibility Masks
CPU compatibility masks allow customization of the CPU features visible to a virtual machine.
vCenter Server compares the CPU features available to a virtual machine with the CPU features of the
destination host to determine whether or not to allow migrations with vMotion.
To guarantee the stability of virtual machines after a migration with vMotion, VMware sets the default
values for CPU compatibility masks.
vCenter Server and Host Management
VMware, Inc. 142