Newer generations of AMD processors do not include 3DNow! processor instructions. If hosts in a cluster have different generations of AMD processors, some with 3DNow! instruction sets and some without, you cannot successfully migrate virtual machines between the hosts. You must use an EVC mode or CPU compatibility mask to hide the instructions.
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
- ♦ 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. - 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.
- In the Cluster Settings dialog box, edit the VMware EVC settings and select the AMD Opteron Gen. 3 (no 3DNow!) EVC mode.
- If you migrated virtual machines out of the cluster, power them off and cold migrate them back into the cluster.
- Power on the virtual machines.
- Power-off any running virtual machines in the cluster, or migrate them out of the cluster using vMotion.
Results
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.
