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Dynamic Load Sharing (DLS) Lossless Setting

  • 1.  Dynamic Load Sharing (DLS) Lossless Setting

    Posted 02-05-2019 07:28 AM

    Hello Everyone,

     

    I’m looking for some guidance on setting up ISL/trunks between an existing 6510 switch and some new 6510 switches.

     

    I have just added six new 6510 switches to two existing 6510 switches creating two 4 switch fabrics. The new 6510’s are running FOS v7.4.1d and the existing 6510 switches are running FOS v7.0.2c. The new switches also have a trunking license but the existing switches do not. The ISL’s run from the old switch to one new switch and that new switch has two trunks connecting to each of the other new switches in the fabric.

     

    ISL Connections:

         New_SW1 <-- Existing_SW

         New_SW1 <-- New_SW2

         New_SW1 <-- New_SW3

     

    My question is should DLS be set to lossless? If so, does it need to be set on both the old and new switch that are ISL’ed together?

     

    Current DLS settings on FOS 7.0.2c switch: “DLS is set by default with current routing policy”

     

    Current DLS settings on FOS 7.4.1d switch: “DLS is set with Lossless disabled”

                                                                           “E_Port Balance Priority is not set”

     

    Are there any other settings I should be concerned with to insure the ISL/tunking connections communicate properly?

     

    Also, a secondary question, I’m looking to upgrade the existing switch and would prefer to avoid an outage if possible. I have read in the forms that the FOS can be upgraded one minor version level at a time without an outage on the fabric (i.e. 7.0.x --> 7.1.x --> 7.2.x ….etc.) basically taking 4 upgrades to get from 7.0.2c to 7.4.1d, is that true?

     

    Thanks in advance for you time.


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  • 2.  Re: Dynamic Load Sharing (DLS) Lossless Setting

    Posted 02-05-2019 10:54 AM
    I'd align the FOS on the entire SAN and set DLS with lossless enabled. E_Port Balance Priority is only supported on the multi-ASIC switches, so your hardware wouldn't accept this option.

    > FOS can be upgraded one minor version level at a time without an outage on the fabric (i.e. 7.0.x --> 7.1.x --> 7.2.x ….etc.) basically taking 4 upgrades to get from 7.0.2c to 7.4.1d, is that true?

    Yes!
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  • 3.  Re: Dynamic Load Sharing (DLS) Lossless Setting

    Posted 02-05-2019 11:51 PM

    Hello,

     

     

    Which routing policy are you running ?

    Isn't DLS auto enabled with Exchange based policy ?


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  • 4.  Re: Dynamic Load Sharing (DLS) Lossless Setting

    Posted 02-06-2019 07:20 AM

    Marian,

     

    Thanks for the replay.

     

    All the switches have DLS set with the default policy “Exchanged Based Routing Policy” but LossLess is disabled. I wondering if LossLess should be enabled. What does it buy us if anything?

     

    Thanks


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  • 5.  Re: Dynamic Load Sharing (DLS) Lossless Setting

    Posted 02-06-2019 10:43 AM

    Hello,

     

    if you dont have FICON i will enable loseless.

     

    Some words from documentation

     

    Lossless mode ensures no frame loss during a rebalance and takes effect only if DLS is enabled.
    Note that “no frame loss” can be guaranteed only when a new additional path is used to do load rebalancing—“no frame loss” cannot be guaranteed on an existing data path that encounters the failure.

     

     


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  • 6.  Re: Dynamic Load Sharing (DLS) Lossless Setting

    Posted 02-06-2019 07:18 AM

    Alexey,

     

    Thanks for the reply.

     

    I agree that upgrading the FOS is needed and we will be doing that very soon, however we need to put the new switches into production service before we can complete the upgrade. Also the existing switch will not get a trunking license so I need to know the best configuration for what I have in place now.

     

    Thanks for the conformation on the ability to upgrade without an outage. 

     

    Thanks


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