Welcome to this Cisco Support Community Ask the Expert conversation. This is an opportunity to learn and ask questions about Cisco Data Center Virtual Machine Fabric Extender (VM-FEX) with Vishal Mehta and Ali Haider.
Cisco VM-FEX collapses virtual and physical networking into a single infrastructure. Data center administrators can now provision, configure, manage, monitor, and diagnose virtual machine network traffic and bare-metal network traffic within a unified infrastructure.
Cisco Data Center VM-FEX partitions the server adapter into multiple vNICs, and each vNIC is assigned to individual virtual machines.
The VM-FEX software extends Cisco fabric extender technology to the virtual machine with the following capabilities:
Vishal Mehta is a customer support engineer for Cisco’s Data Center Server Virtualization TAC team based in San Jose, California. He has been working in the TAC for the past three years with a primary focus on data center technologies such as Cisco Nexus 5000, Cisco UCS, Cisco Nexus 1000v, and virtualization. He presented at Cisco Live in Orlando 2013 and will present at Cisco Live Milan 2014 (BRKCOM-3003, BRKDCT-3444, and LABDCT-2333). He holds a master’s degree from Rutgers University in electrical and computer engineering and has CCIE certification (number 37139) in routing and switching and service provider.
Ali Haider is a customer support engineer for Cisco's Data Center Server Virtualization TAC team based in San Jose, California. He has been working in the TAC for the past 14 months with a primary focus on data center technologies such as Cisco UCS, Cisco Nexus 1000v, and virtualization. He has completed his undergraduate degree from University of Texas at Austin in management information systems. He currently holds CCNA and VCP certifications.
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let me first congratulate you on selecting such a great topic. I don't know much about this so I'll start with some basic questions:
- Is VM-FEX feature supported only all mezzanine cards, or to be more precise does it work for cards like M81KR or 82598KR-CI? BTW, is Cisco still manufacturing non dynamic interface type mezzanine cards?
- As far as I understand VM-FEX feature, it allows VM to communicate directly with particular VIC in mezzanine card in a way it tunnels through the hypervisor. Does it mean that by not allowing hypervisor to control VIC we are losing some of hypervisor features (for example Vmotion)?
- Is VM-FEX available only for ethernet type of traffic or it also works for fibre channel and FCoE?
This event is not a live webcast. It's a two-week online discussion. There are no slides available for download. If you have any questions on this topic, you would just need to post it here and the experts will answer.
Please see below link for the details and caveats on VM-FEX technology
UCS step-by-step configuration guide for VM-FEX:
Additionally you can register online to https://www.ciscolive.com for free and can access all Sessions
Search for VM-FEX and it will list all Cisco Live sessions with Videos and PowerPoint
For next 2 weeks if you have any questions on VM-FEX please feel free to post it here
Thanks for asking these good questions.
Q. Is VM-FEX feature supported only all mezzanine cards, or to be more precise does it work for cards like M81KR or 82598KR-CI? BTW, is Cisco still manufacturing non dynamic interface type mezzanine cards?
Currently VM-FEX is available only for Cisco VIC (Virtual Interface card) adapters that include virtualization capability. For UCS-B series this includes M81kr, VIC1240 and VIC1280. For UCS-C series rackmount servers we offer VIC1225 and P81E Virtual interface cards that support VM-FEX capability.
Q. As far as I understand VM-FEX feature, it allows VM to communicate directly with particular VIC in mezzanine card in a way it tunnels through the hypervisor. Does it mean that by not allowing hypervisor to control VIC we are losing some of hypervisor features (for example Vmotion)?
VM-FEX supports two modes: Standard Mode and High Performance mode. In standard mode, traffic to and from a virtual machine passes through the distributed virtual switch (DVS) and the hypervisor. In high-performance mode, traffic to and from a virtual machine (VM) bypasses the DVS and hypervisor. Traffic travels directly between VMs and the virtual interface card (VIC) adapter. Both modes support vmotion capability. During vMotion, the hypervisor reconfigures links in high-performance mode to be in standard mode, transitions the link to the new hypervisor, and then reconfigures the link to be in high-performance mode
Q. Is VM-FEX available only for ethernet type of traffic or it also works for fibre channel and FCoE?
VM-FEX is only capable of handling Ethernet traffic. Cisco VIC adapter is a converged network adapter, and presents separate FC and Ethernet interfaces to the hypervisor. All FCOE processing is done at the adapter-level. From the perspective of the hypervisor FC and Ethernet traffic is separate and isolated. FC traffic will be processed as usual by the hypervisor and it will be processed and sent as FCOE traffic from the adapter to the fabric Interconnect.
Hope this answers your questions. Please refer to VM-FEX configuration guide for more details.
The maximum number of dynamic vNIC actually depends on the following factors:
1. Type of the blade (full-width/half-width)
2. Virutal Interface card
3. Generation of Fabric Interconnect (6100/6200 series)
4. Operating System (OS)
Below link shows the maximum number of dynamic vNIC for latest UCS release 2.2
The default value is 54 and range is from 0 to 256 as listed below in configuration guide:
Hope this answers your question
Vishal and Ali
Thanks for your question Sarah. The number of Dynamic vNICs can be modified by changing the Dynamic vNIC Connection Policy located under the LAN tab. However, this is a disruptive change that requires a reboot on all the hosts that the Dynamic vNIC Connection policy is associated with, and therefore it has to be planned and done during a maintenance window. Please refer to the link below for instructions on changing the dynamic vNIC connection policy.
Thank you for asking this question.
Easy VM-FEX Deployment Tool is not being developed for the newer releases (2.1 onwards)
For UCSM 2.0 version it was available for download directly from UCSM GUI
Hope this answers your question
A VM can have multiple dynamic vNIC assigned to it at a time.
The functionality from VM point of view is same for both VM-FEX / Nexus 1000v setup