Can VMs share the allocated VCPUs between them?

[essam_farrag]

Hello ,

we have UCS C220 M35BE, with 8 logical processors (2 processor sockets * 4 cores per socket).
there two VMs already deployed:
- CUCM VM > use 4 VCPUs
- UCCX VM > use 4 VCPUs
the question is, can i deploy new virtual machines for CUC, IMP or recording ? is it will work ? is it supported by Cisco ?
can virtual machines share the VCPUs between them ?

Thanks

Essam 

[HARIS_HUSSAIN]

No CPU Core Sharing is not SUpported

Refer Below

http://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/collaboration-virtualization-sizing.html#generalrulecpu

Must map 1 VM vCPU core to 1 physical CPU core.

• For example, if you have a host with 12 total physical cores, then you can deploy any combination of virtual machines where the total number of vCPU on those virtual machines adds up to 12.

[Rajan]

Hi Essam,

Please refer the below link:

http://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/collaboration-virtualization-sizing.html#generaloversubscription 

No hardware oversubscription is allowed for UC applications.

Must map 1 VM vCPU core to 1 physical CPU core.

• For example, if you have a host with 12 total physical cores, then you can deploy any combination of virtual machines where the total number of vCPU on those virtual machines adds up to 12.

HTH

Rajan

Pls rate all useful posts

[HARIS_HUSSAIN]

In you case you need to redesign the CPU Allocation based on your User Size.

You can use the tool to check differnt combinations

http://docwiki.cisco.com/wiki/Readme_for_Cisco_Collaboration_Virtual_Machine_Placement_Tool

In you case if you want to change the CPU allocated to Exsisiting CUCM/UCCX you need to reinstall VM with New VM Settings and do a backup restore.

Please rate and mark correct as applicable 

Thanks

Haris

[essam_farrag]

thanks a lot Haris ,

is there any way to resize the CUCM/UCCX VCPUs ? or i have to rebuild the cluster?

[Chris Deren]

Take a look at "Resize Virtual Machine" section in this doc for re-sizing VMs guidelines:

http://www.cisco.com/c/dam/en/us/td/docs/voice_ip_comm/uc_system/virtualization/virtualization-software-requirements.html#resize_vm

[Mohammed al Baqari]

Just a note to add, if you deploy collaboration VMs using OVAs they take care of resource allocation automatically. The OVA will have reservations for CPU and Memory preconfigured to match the size of deployment you select during OVA template import (1000, 7500, 10000, etc).

Having this said, you can try importing OVA for CUC, for example, and if you don't have enough resources the import process will fail. Depending on the type of the application, some VMs (for example CUCM) resrves full vMemory while others reserve 70%, etc. 

In summary as long as you use OVAs, your resource allocation will be taken care of automatically and you should be well covered by Cisco support.

Another point, Cisco are very preserved in resource allocation for collab VMs due to the nature of audio. However, I have tried removing the reservations in many labs and most of the time you don't notice a difference. But I don't recommend doing this in production especially with heavy loaded enviroments 

[essam_farrag]

as per the document. if i need to remove VCPUs from VM, I have to make DRS.

[HARIS_HUSSAIN]

Yes that is correct, You have to perform a DRS Backup, Shutdown/Disconnect VM and rebuild with same version, IP and other settings then perform a DRS Restore.

While rebuilding you can import the OVA Templates as per sizing requirement depending on your environment(1000, 2000,7500, 10000, etc User capacity).

Thanks

Haris