Follett Hardware 5300 Enabling Trigger Mode

In today's post we'll see what is EVC, in which example is needed and how nosotros tin can enable it on VMWare cluster.

What is EVC

Allow's see get-go what is EVC – source VMWare:

EVC stands for Enhanced vMotion Compatibility. This is a vCenter cluster feature which simplifies vMotion compatibility problems across CPU generations. EVC automatically configures server CPUs with Intel FlexMigration or AMD-V Extended Migration technologies to be compatible with older servers.

Later EVC is enabled for a cluster in the vCenter Server inventory, all hosts in that cluster are configured to present identical CPU features and ensure CPU compatibility for vMotion. The features presented by each host are determined by selecting a predefined EVC baseline. vCenter Server does not permit the improver of hosts that cannot exist automatically configured to be compatible with the EVC baseline.

At present that nosotros know what is EVC, let me tell you scrap about how nosotros constitute out that we take to enable this characteristic.

In which case is EVC needed

Nosotros were asked by one of our customers to practice a complete upgrade of the VMWare infrastructure from version half-dozen.0 to 6.5. The customer has a cluster of 15 HP DLE360 G9 servers and lately he added two servers more.
After these two hosts take been added, some more VMs take been deployed in the cluster and they "landed" on these two ESXi hosts.

At that moment, on these two hosts were running VMs that migrated via DRS from the "older" hosts and also new VMs that were installed on these 2 new hosts from the get-go.

Prior starting the upgrade nosotros did some checks and we noticed that the new VMs that were installed on the new added hosts, could non migrate to the older hosts. When trying to manually migrate them, we were getting this error:"The target host does not support the virtual automobile'due south electric current hardware requirements. To resolve CPU incompatibilities, use a cluster with Enhanced vMotion Compatibility (EVC) enabled. See KB commodity 1003212."

Every bit y'all can see, vCenter is alert that there are CPU incompatibilities between the hosts and is suggesting to solve this trouble by enabling EVC on the cluster.

It seems that the lately added hosts are having a unlike CPU generation. So let'due south run into their configuration and their supported EVC modes.

The following ii screenshots were taken after EVC has been activated and ESXi hosts accept been upgraded. And so it can be noticed here that EVC is already activated in Intel "Haswell" Generation.
But let'due south focus at this betoken at the Processor Type of these two kind of hosts.

Hither is the blazon of hosts 1-15:

And this is the type of hosts 16-17:

Indeed, the CPU generation of the new hosts is dissimilar than the previous ones and the highest common CPU Generation Baseline for these 17 hosts is Intel "Haswell" Generation. The offset 15 hosts are already running with this Baseline, we only have to downgrade the Baseline from Broadwell to Haswell on the two new hosts .

Activate EVC

After finishing previously mentioned checks, we tin can go ahead with EVC activation. To activate information technology, we accept to select the cluster, go to configuration, select VMWare EVC and so Edit.
Because in our case, the servers are equipped with Intel CPUs, we take selected Enable EVC for Intel Hosts and chose VMWare EVC Mode to Intel Haswell Generation. After vCenter did some checks, we got this compatibility error for the final two hosts.

As the error suggests, in club to exist able to enable EVC on the cluster, we have to ability off all the machines running on these two new hosts.
Later the VMs have been powered off, we enabled Maintenance manner on hosts.

Once the hosts are in Maintenance manner, we'll set once more VMWare EVC Manner to Intel Haswell Generation and now we'll not go errors anymore. At this point we can successfully activate EVC.
After EVC is activated, we can disable Maintenance manner on these hosts and we can power on the machines. The new hosts will start at present in EVC Haswell generation mode.

Now EVC is working on the entire cluster and we can see that the VMs from the new hosts tin can migrate to the older hosts without any problem.

Conclusion

I volition recommend to actuate EVC from the beginning, even if you lot have hosts of the aforementioned blazon and no plans for expansion. You will save this way time and avert potential problems.
You can likewise exercise it later you added new hosts with a dissimilar CPU Generation, merely this could bring you some inconvenience, cause it might be possible to ability off some VMs before beeing able to activate EVC.
Only either you lot exercise information technology at the beginning or after adding a new host, EVC should exist active in club to maintain the functionality of vMotion across all ESXi hosts in the cluster.

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