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Community Member

UCS Design Best practice for vMotion


We are deploying a new UCS domain with 8 chassis and 50/60 B200M3 for installed an VMware infrastructure 5.0

For each ESXi, we need :

2 vNIC dedicated to Management Network

2 vNIC dedicated to vMotion

4 vNIC dedicated to srv

These vNIC will be configured into Template Service Profile deployed to all B200M3.

For each pair of vNIC, a vNIC used fabric A, a vNIC used fabric B.

We could have vMotion between all server.

The VMware vSwitch will used either vNIC_A or vNIC_B such as VM and loadbalancing algo.

Do we have a design in order to confine the vMotion vlan to UCS domain ?  I means to not trunk dedicated vMotion Vlan on uplink

Many  thks for your advice.

Best regards.


Cisco Employee

Re: UCS Design Best practice for vMotion

The only way to try to contain VMotion traffic the same fabric would be to set the vmnic uplink preference for the vmotion vmkernel so that vMotion always "prefers" to use the same Fabric uplink (A or B).

This is what most folks do.  VMotion is not constant traffic, just bursty - so confining it to one fabric interfonnect is a good design choice if you don't want it to traverse northbound of the UCS domain.



Community Member

Re: UCS Design Best practice for vMotion

hi Roberts,

Thx again for your reply to my new question.

The vmnic uplink preference set for the vmotion vmkernel is done on VMware environnement. Any configuration on UCSM ?

You mean that you configure one vmnic as active adapter and one vmnic as standby adapter ?


All these B200M3 have only one VIC1240. if you lost FI-A, all trafic swtich to FI-B for all chassis

but if we lost IOM-A of chassis 2, the vmotion trafic for this chassis uses FI-B but all other chassis keep to use FI-A ????



Cisco Employee

Re: UCS Design Best practice for vMotion

No need to change anything on UCSM side for the vMotion requirment. All required is that the vmnic which corresponds to FI-A is set as primary on each host for the VMkernel used for vMotion.  This keeps all vmotion traffic local to one FI without leaving the system.

At any time if you lost an adapter, IOM or FI, they traffic would failover to the standby vmnic assigned to the vmkernel - so you will have full redundancy - you're simply setting a sticky "preference" of which link to use.  In the case where you lost IOM-A on Chassis 2, that VMotion traffic would then traverse the northbound network to reach the other fabric - not a big deal as vMotion is not that bandwidth demanding.


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