[cisco-voip] Changing vCPU Quantities

[Daniel Pagan]

I’ve heard of this as well and actually have an open case that will require a rebuild of CUC in order to add an additional vCPU. From what I recall, it can be done but Unity won’t utilize the additional core unless it’s detected during the install process. CUC, from what I know, is the only UC application to which this caveat applies.

It turns out there’s a doc that says if you’re using UM features, the servers should be spec’ed with more than a single vCPU… but this caveat isn’t mentioned in any of the OVA template readme files for some reason.

Here’s the doc:

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/connection/10x/supported_platforms/10xcucspl.html -- Search for “Unified Messaging” - you’ll see a chart where a reader has to interpret that a single vCPU doesn’t support single inbox. Again, could be better documented IMO :)

I personally request our deployment engineers, when possible, to stay away from single vCPU UC VMs if they’re coming to managed services, especially for CUCM, since we do lots of trace collection and have had issues where the gzip process consumes all available CPU cycles. Add CUC UM to this and more reason to avoid it for CUCM and CUC in most cases. This one was already built out before it came our way, but I still think the caveat of UM features needing 2 or more vCPUs should be in the OVA read me.

- Dan
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From: cisco-voip [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Anthony Holloway
Sent: Wednesday, July 27, 2016 1:17 PM
To: Cisco VoIP Group <cisco-voip at puck.nether.net>
Subject: [cisco-voip] Changing vCPU Quantities

Hi Everyone,

I have been telling people on this list<http://cisco-voip.markmail.org/thread/rrege2ktkvjha2oa> for a while now, and for that matter, in person too, that you can just shutdown the VM and modify the vCPU count per VM and then power it back on.

In fact, I know I've done this a half a dozen times in the past.  However, for CUC, a colleague of mine just uncovered the following bullet point:

"Adding vCPU is supported for all apps except Unity and Unity Connection, but requires VM to be shutdown first."

Source: http://docwiki.cisco.com/wiki/Unified_Communications_VMware_Requirements#Resize_Virtual_Machine

So, with CUC being the exception, it would stand to reason that CUC requires a DRS backup, new OVA deployment, then DRS restore to change the vCPU count, correct?

To add to the confusion, PDI is even stating<https://supportforums.cisco.com/discussion/12111866/changing-cpu-core-count-esxi-unity-connection-86> in certain cases online that changing the vCPU count without a DRS backup.restore is support.

So, what do you know about this?  Is CUC really different from the other apps, or is this a case of bad documentation?

Thanks.
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