vMotion of CUCM and CUC

[wreed_cisco]

I am continuously told by Cisco UC engineers you cannot live vMotion CUCM and CUC, yet the Cisco Virtualization Wiki says otherwise. Anyone care to elaborate?

If the UC app is listed as "Supported with Caveats", which CUCM and CUC are, then support is as described below:

• Migration of UC VMs that are live and processing live traffic is supported, but note that Cisco testing cannot cover every possible operational scenario. Testing has shown there is a slight risk of calls in progress being impacted for a few seconds as the migration occurs, with worst case result of the affected calls being dropped. If vMotion is suspected as the cause of dropped calls, customers should gather appropriate application logs as well as performance data from VMware vCenter and send to Cisco TAC for analysis.

[Gregory Brunn]

I can say I have seen someone vmotion CUCM and CUC from host to host in the middle of the day and caused a major outage. This was years ago and I am pretty sure it was across a wan link. I would not recommend doing this. Instead my recommendation would be if you have to do it do it doing a maintenance window or do it as a cold migration. I typically take the cold migration route. Last time I had to move vms from one host to another I did a cold migration vm by vm. This works well if you have true redundancy you barely notice the phone switch from one CUCM to the other.

What is your end goal or what your trying to do is just worried about redundancy if you lose one host... this is built into CUCM/ CUC clustering and design.

[wreed_cisco]

My goal is to try to understand why Cisco.com says its OK to do in a maintenance type scenario, yet their field engineers say it cannot be done.

[Chris Deren]

Safest and supported method for most UC apps is to shutdown the application and perform vMotion while it's shut down. I have done it hundreds of times with many apps without issues.  Vmotioning running VM is not supported by Cisco, but I have seen that go without an issue too, though proceed with caution.

[Gregory Brunn]

Shutting down and moving is called a cold migration. Happy to hear Chris say he has seen it work. I have not nor would I recommend it unless it is not a major system or critical for your business.

[Chris Deren]

Greg,

Why would you not recommend it if it's supported?

[Gregory Brunn]

It is supported with caveats that is might cause issues.
Cold migration I fully would recommend. Maybe my statement was not clear.