#EngineersUnplugged ACI Edition with Colin Lynch and Hal Rottenburg

About ucsguru

Principal Consultant and Data Center Subject Matter Expert. I do not work or speak for Cisco or any other vendor.
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2 Responses to #EngineersUnplugged ACI Edition with Colin Lynch and Hal Rottenburg

  1. Subhash says:

    Hi Colin,

    I’m following your blog from long back, its really awesome blog to understand CISCO UCS.

    I need your assistance to get clear on below are my questions.

    1) we know that each vNIC will pin to only one uplink/pc. When we have two or more uplinks, to which uplink the vNIC pinning will happen?(in dynamic pinning).

    2) In case of Dynamic pinning the vNIC, what happens if all the FI uplinks are down? will the vNIC traffic moves to another FI? If so it requires to be enabled h/w failover right?

    3) in manual pinning, when the uplink failure!! the vNIC traffic moves to another FI uplink right? for this the vNIC should be created with h/w fail over? what happens if the h/w failure is not enabled?

    could anyone pl help me to get clear on this 🙂

    Thanks in Advance,

    • ucsguru says:

      Hi Subhash

      In Answer to your questions:

      1) Each vNIC is pinned to an uplink via a round robin algorithm, so is you have 8 vNICs and 2 uplinks you should end up with 4 on each. This vNIC to Uplink association will remain until and uplink fails, and the vNIC is repined, or the Service Profile is re-associated and a different uplink may be chosen.

      2) If there are no available uplinks for a vNIC to pin to then that vNIC will not come up. If fabric failover is enabled for that vNIC and there is a suitable uplink available on the other fabric then the vNIC will failover to the other fabric using the alternative vif path.

      3) If you have hard pinned a vNIC to an uplink, and that uplink fails, then the vNIC will go down, it will not dynamically re-pin. If fabric failover is enabled then above rule applies.

      As always static pinning should only be used for very specific use cases, In my view always best to just leave dynamic pinning to do its thing.

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