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Nocriton
Contributor
Contributor
‎10-07-2011 01:24 AM

Run the vCenter on a dvSwitch?

Hi

Currentyl we're running two clusters (vSphere 4.1) - one with a Standard Switch and one with a dvSwitch.

Now we have to replace the Hardware of the first Cluster with the Standard Switch, and we think about 10G Eth.

With 10G we will have only two nic, and we want to use the dvSwitch here, too.

This will lead us to the problem, that the vCenter Server will have to run on a dvSwitch.

From my understanding, it's not possible to change the dvSwitch Network Connection of a VM, while the vCenter is offline.

But how can i get the vCenter online on the dvSwitch after a restore for example?

The last time i did some research on this, was when the dvSwitch was introduced, maybe something has changed and i missed it?

Best regards

Nocri

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PduPreez
VMware Employee
VMware Employee
‎10-07-2011 04:43 AM

Hi Nocri

From my understanding, it's not possible to change the dvSwitch Network Connection of a VM, while the vCenter is offline.

But how can i get the vCenter online on the dvSwitch after a restore for example?

As far as I am aware your statement is correct.

There are options to recover:

If you have to restore the Whole VM (VC VMFS folder) you would need to restore it on the original host it was running on at the time of backup, but also the Original Datastore.

If you manage to achieve this, the VM should start up and have network connectivity.

I normally Disable DRS on vCenters and pin it to host 1 so you always know where it is unless host 1 fails (HA is still enabled for the vCenter)

The other option is restoring the VM and you cannot recover it on the original host or datastore

In this case you would need to remove a NiC from one of the hosts to create a vSwitch. You then restore vCenter to this host, connect it to the vSwitch, as soon as it is up and running you connect it back to vDS, delete vSS and add pNIC to vDS. Quite a process I know, but possible.

When running vDS it is important to have high redundancy and proper backups off your vCenter. (vCenter Heartbeat comes to mind)

The best practice is still to seperate the Management and VM Traffic, but not always possible as in a 2 x 10Gb pNIC scenario

Hope it helps, and please award some points if it does Smiley Happy

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Nocriton
Contributor
Contributor
‎10-07-2011 05:15 AM

Ok, i've spend another two hours on searching - this is what i found out:

There are three different ways a portgroup can be configured:

  • Static Static Binding (Default): means that the dvPort is assigned to the virtual machine at  configuration time. When all the ports are booked by virtual machines,  it is not possible to connect to any more virtual machines, regardless  of whether the connected virtual machines are powered up or not, and an  error message is displayed.
  • Dynamic Dynamic Binding: means that the dvPort is assigned at the moment of powering the virtual  machine up. This option allows for over committing the number of  dvPorts.
  • None (Ephemeral ports): (Ephemeral  Ports or No Binding) this behavior resembles the behavior in the  standard vSwitch. If you select this option, the number of ports are  automatically set to 0, and the Portgroup allocates one port for each  connected virtual machine, up to the maximum number of ports available  in the Switch.

Found this here: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=101059...

So Ephemeral ports behave like standard vSwitch? I started to take a look at this and found this:

http://www.vcritical.com/2011/05/the-secret-of-ephemeral-port-groups/

"The key point to note is that port groups using ephemeral bindings behave very much like a Standard vSwitch — even with vCenter Server powered off, administrators have the ability to connect directly to an ESXi host and reconfigure VM networking."

I think we will create a single Ephemeral dvPortGroup with the VLAN ID of our vCenter Network. In the case of an emergency, we will have the posibillity to change the settings to this PortGroup directly on the host. With the vCenter back online - we will have the posibillity to edit everything else.

Thx

Nocri

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PduPreez
VMware Employee
VMware Employee
‎10-07-2011 05:43 AM

Hi Nocri

WoW - Thanks for this valuable information, I learned something new Smiley Happy

There are some disadvantages discussed in  http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=102231...

But having the limitation of only 2 pNICs does make this an excellent solution and I will surely include this if I have to design around this limitation

So yes, I would also create a non used backup Ephemeral dvPortGroup with correct VLAN.

Just some extra input:

Remember to set your portgroup Priorities in accordance

always but vMotion lower priority than VM Portgroups

Have a nice weekend :smileycool:

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