vDS to vDS Cold migration

[Jwoods]

Is there an easier way to cold migrate a VM from vDS to vDS without removing the vNIC?

My current environment has 2 physically separated datacenters with about 15 hosts in each.  vCenter is configured with each physical datacenter having a single 15-host Datacenter/Cluster and vDS defined for each.

The current process prior to cold migration is to remove the vNIC(s), then migrate the VM to the desired location.  Is there a better or easier way of doing this?  Would labeling my dvPgs exactly the same resolve this issue?

[peetz · Accepted solution]

For such scenarios we have created the following workaround in our environment:

Create an extra vDS (we named it TransferSwitch), add all hosts from all datacenters/clusters to it, but without any physical uplink.

A cold migration process from one datacenter/cluster to another is then done in three steps:

1. Connect the VM's NIC to the TransferSwitch

2. Cold migrate the VM to the destination

3. Connect the VM's NIC to the destination vDS

This avoids removing/re-adding the VM's NICs and all consequences (like a new device being detected in the Guest OS, with a different MAC address).

You may create the TransferSwitch just temporarily for each VM migration, but we decided to just keep it permanently.

- Andreas

[Jwoods]

Andreas,

Thanks for the response.  I'm a bit confused here.  Bare in mind that I'm still learning about dvSwitches and their intricacies.  With that, isn't it true that a  dvSwitch needs at least one uplink for each host for communication with one another?  If I create a dvSwitch with no uplinks wouldn't vcenter give a warning requesting the uplink?

[peetz]

No, you won't get a warning. It's perfectly okay to create a vDS without any physical uplinks (just as it is okay to create a standard vSwitch without uplinks).

Of course, a VM attached to this vDS won't be able to communicate over the network. However, you only attach a VM to that vDS for moving it between clusters while it is powered off.

[Jwoods]

Andreas Peetz wrote:

...just as it is okay to create a standard vSwitch without uplinks

I considered this, but wasn't sure if the same applied to vDS.  Many thanks for your help!