Released: Exchange Server Role Requirements Calculator 8.3

Today, we released an updated version of the Exchange Server Role Requirements Calculator.

This release focuses around two specific enhancements.

  1. Exchange 2016 designs now take into account the CU3 improvement that reduces the bandwidth required between active and passive HA copies as the local search instance can read data from its local database copy.
  2. The calculator now supports the ability to automatically calculate the number of DAGs and the corresponding number of Mailbox servers that should be deployed to support the defined requirements. This process takes into account memory, CPU cores, and disk configuration when determining the optimal configuration, ensuring that recommended thresholds are not exceeded.

As a result of this change, you will find that the Input tab has been rearranged. Specifically, the DAG variables have been moved to the end of the worksheet to ensure that you have completely entered all information before attempting an automatic calculation.


As with everything else in the calculator, you can turn the automatic calculation off and manually select the number of Mailbox servers and DAGs you would like to deploy.

For all the other improvements and bug fixes, please review the Release Notes, or download the update directly.

As always we welcome feedback and please report any issues you may encounter while using the calculator by emailing strgcalc AT microsoft DOT com.

Ross Smith IV
Principal Program Manager
Office 365 Customer Experience

Comments (13)
  1. Dan says:

    I get the following error
    “cannot calculate DAG until SpecInt2006 values are populated”

    All values are populated, including the SPECint2006 Rate Value

    1. @Dan – there is a bug that requires you to populate the SpecIntRate2006 value into the secondary datacenter row even if you do not have a site resilient deployment. That will be fixed in the next release.

      1. Deji says:

        I should have come to the thread first before banging my head so hard against the wall trying to figure out the “Must Populate SPECint” error :).

        This new version is a great improvement, though. Nice work

  2. Adam says:

    The links all link to Ex2013, is that correct?

  3. Mahesh Aralelemath says:

    Wow looks very interesting, really great

  4. Chris says:

    Looks good Ross.

    I see that the “Automatically calculate DAG solution” option frequently returns a recommendation for servers with 128GB of memory – is the 96GB best practice advice being relaxed?

  5. Frank says:

    did anybody know where I can submit bugs?

  6. Doyle says:

    I used this Calculator to plan out our Exchange 2016 environment with a backup methodology of Exchange Native Data protection and a lagged copy. Unfortunately, when you create the scripts for creating databases, the setting for ‘RetainDeletedItemsUntilBackup’ is set to True. If you’re using NDP, no backup occurs. Why wouldn’t it set that option to False on the Database? Thanks!

    1. Doyle says:

      Never mind. Looks like the updated the calculator in version 7.9 in June with the corrected setting. I used the calculator and built our environment in March.

  7. Tim says:

    Ross – any idea when we can expect to see solid state storage (SSDs, etc) represented in the calculator?

  8. Steven says:

    Can you tell me if BitLocker is accounted for in the calculator? Should we add some Mega-Cycle multiplication factor to account for that?

    Let me know. Thanks.


  9. d says:


    Using the automatic calculation, I get a 2 DAG solution, with 7 servers / DAG. But when I go to the role requirements page, the environment configuration does not add up. It is actually saying double the resources per DAG, and 4 times the resources in the environment. This is a bit confusing from the pop-up. Are these supposed to match?
    Also, in an active active (multiple DAGs config), it will only put DR copies in the secondary site (as in Active / Passive) config.

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