What are different between software VM-FEX and hardware VM-FEX?

[Hele Du]

Hi everybody,

I am confuse software VM-FEX and hardware VM-FEX.

Does the software VM-FEX is Emulated mode and hardware VM-FEX is VMdirectpath mode?

If i design a VM-FEX, is there must have nexus 1000V or not ?

Is  Nexus 1000V and VM-FEX must work together or select one of them?

[Walter Dey]

Have a look at http://keepingitclassless.net/2013/06/cisco-vm-fex-and-the-nexus-1000v/

VM-FEX in hardware requires on the host side a VIC adaptor, and a UCS FI or N5k as a switch (and control plane)

VM-FEX in hardware has 2 submodes (PTS = Emulated Mode) and UPS (path Through)

VM-FEX makes use of the VEM module (same as N1K; it is operated in a different mode however)

VEM can do N1k local switching or VM-FEX path through, but not both !

[Hele Du]

Hi Wdey,

Thank you for your answer.

So what is VM-FEX in software mode ?

[Walter Dey]

If you are interested in the performance impact of VM-FEX, specially SAP, see

http://scn.sap.com/community/it-management/virtualization/blog/2013/08/27/sap-batch-workload-performance-on-linux--vsphere--ucs

Walter.