UCS VIC with MacVtap vs Direct device assignment

[Jagath003]

Hi all,

What is the difference between using UCS VIC with and without Macvtap driver in KVM?

Are there any performance issues or effects in the case of VM Live migration?

(According to the UCS-KVM-VMFEX configuration guide, Macvtap driver is used for VMFEX)

Reference: Figure1 of the following document

http://www.cisco.com/en/US/solutions/collateral/ns340/ns517/ns224/ns955/ns969/c45-608744-00_RedHat_aag.pdf

Thanks
Jagath

[mipetrin]

Hi Jagath,

The Macvtap driver only comes into play if you wish to utilize VM-FEX on a Cisco UCS Blade along with a Cisco VIC and RHEL KVM.

For a list of benefits relating to VM-FEX, please see the following links:

http://www.cisco.com/en/US/netsol/ns1124/index.html#~benefits

http://blogs.cisco.com/datacenter/cisco-virtual-machine-fabric-extender-vm-fex-and-cisco-vic/

Thanks,

Michael

[Jagath003]

Michael,

Thanks for your reply.

I wanted to know the reason for using macvtap driver with VMFEX. What about the direct assignment of

VM vNIC to CNA vNIC as in VMware ESX?

Thanks

Jagath

[mipetrin]

Jagath,

The following Cisco Document explains the different components use in VM-FEX for KVM, including the MacVTap driver:

Cisco UCS Manager VM-FEX for KVM GUI Configuration Guide - KVM Concepts

It also links to the following site for further details on the MacVTap driver:

http://virt.kernelnewbies.org/MacVTap

Essentially, this MacVTap driver, within Red Hat KVM, is what is allowing you to provide the direct assignment of the virtual machine vNIC to the CNA vNIC.

Hope that helps

Thanks,

Michael

[Jagath003]

MIchael,

Thanks. 

Jagath