Two phsycial Datacenters with only one Distributed Switch and Datacenter in VMware.

[vmwarelicense12]

We have to physical separated Datacenters, but want only One Distributed Switch and one Datacenter in our VMware environment.

Then we want to separate our physical Datacenters with clusters instead.

Could that be a problem?

[birend1988]

Yes, you can configure the separate cluster for 2 DC.

[vmwarelicense12]

But could there be a design problem in that?

[IRIX201110141]

Thats exactly what we have here... but Datacenter here means Serverrooms on the same campus. For a easier living we have vDS and separate vSphere Clusters connected.

Regards
Joerg

[jburen]

No, there's no design problem. What you want to build is a stretched datacenter. So one vCenter datacenter stretched across two physical locations. You don't have to create two separate clusters. You can create one cluster like 'Production' and configure (anti)affinity rules for your VM's if you want to.

[depping]

Creating a "stretched datacenter" with a single cluster only makes sense if your storage is also stretched. If you have 2 storage platforms and 2 independent rooms, or building, I would create 2 clusters. Maintaining those rules just becomes complex, and is failure prone.

[vmwarelicense12]

But is it risky to only have one vdswitch, when we have to server rooms? I am worry about updating a dvswitch when when we only have one dvswitch. What if something goes wrong when updating the dvswitch. Then nothing is working any more, and both server rooms is down.

[sjesse]

Thats why you should take regular backups of the dvswitch settings, its not much worse having 1 then 2, as you would bring down one or the other. If the networks are the same in both and the storage is available in the both, I'd do just one. We can't do it because we won't stretch layer 2 across DCs.

[vmwarelicense12]

If I have one dvs for each server room, only half of our servers fails in case of disaster when upgrading dvs, but If i only have one, all servers fail.

So do you really mean that it is OK to only have one dvs when having 2 server rooms?

[NathanosBlightc]

Because there is no dependencies for VM network traffic handling of VDS (Data Plane) to the vCenter Server and this plane's duty remains locally on the ESXi host side, no need to worry about if you configure single VDS for both site, even there is one single vCenter Server and it fails in one of your sites. VM traffics on healthy site will work even in vCenter failure of other site cause by a massive disaster. But you can't do any managing operation on VDS (Management Plane) until the vCenter is down.

Whenever you configure a VDS in a datacenter (even with two server rooms and there is two ESXi clusters) in moment of VDS creation and initial configuration, vCenter really will specify just criteria and rule for the Hosts Networking, not exactly doing frame switching instead of them! It's somewhat like that you want to config two physical stacked Switch, each of them is installed in different site ... So you can deploy a Single vSphere Distributed Switch in two separated server rooms with separated clusters without any concern.

[vmwarelicense12]

I am not worried if our vCenter fails, but when upgrading the dvs. If upgrade process push upgrades to all ESXi and it breaks, no ESXi servers have network connection?

[NathanosBlightc]

If the supported version of VDS by your ESXi version is higher than your hosts version (in other word you have a VCSA with higher version than its managed ESXi) you cannot add the ESXi to that VDS anyway. I have a similar situation and for a testing situation we should downgrade one of our ESXi to an older version. So the VDS prompt and error that host is not supported by this distributed vSwitch, but that ESXi and all of VMs belong to this host still had their network connectives by their recent dvPortGroup, until if you want change them! But at last I had to revert back that ESXi to the last version (upgrade it) to work correctly with my VDS