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Andre Schoeman's avatar
Andre Schoeman
Copper Contributor
Jan 23, 2018
Solved

Exchange Server Role Requirements Calculator: DAGs required

I have a quick question regarding the “Exchange Server Role Requirements Calculator”.
I have a medium sized Exchange 2010 Environment that I would like to upgrade to Exchange 2016.
The current Exchange 2010 design is based on an Active/Passive design with a Single DAG that is shared across the 7 Mailbox servers. We have around 5500 mailboxes spread across 10 databases.
When I came to put all this detail into the “Exchange Server Role Requirements Calculator” it suggested I have
• 6 Servers in Active site
• 3 Servers in Passive site
I agree with the server design but were a bit surprised when it suggested I have 9 Database Availability Groups? Is this correct? Why can’t I have just one DAG like in my Exchange 2010 environment?

 

In the attachments:-

  • ExchangeCalc9.1.pdf - Calculator populated with my values
  • ExchangeCalc9.1-Result.pdf - Calculator's recommendation for 9 DAGs

You can force the Calculator to use 1 DAG but then it blows the server configuration

  • ExchangeCalc9.1-WithOneDAG-Result.pdf (Cores and CPU highlighted in RED)

 

 

 

Exchange Server
  • Andre Schoeman's avatar
    Andre Schoeman
    Jan 25, 2018

    Finally, I think I know what the problem is - My SPECINT2006 value was way off - I downloaded this tool "Exchange Processor Query Tool" https://gallery.technet.microsoft.com/Exchange-Processor-Query-b06748a5 and it calculated my SPECINT2006 value to be 645. Now the Calculator works correctly and recommends 1 DAG :-)

7 Replies

  • Deleted's avatar
    Deleted
    Jan 24, 2018

    The calculator also assumes you are calculating for 4 copies of DB and you should check the second tab to see the calculation which it did. also the database copy layout tab

    • Andre Schoeman's avatar
      Andre Schoeman
      Copper Contributor
      Jan 24, 2018

      Here are the values. I understand that you would have 4x Database Copies per server - That is correct and there are 3 copies of a Database instance replicated - Two on the Primary Datacenter and One on the DR Datacenter.

       

      But where do the 324 copies come from? I know that 9 x 36 = 324 - But that suggests I have 9 DAGs
      Surely then the Database Copy Instance Configuration values should be multiplied by 9...?

       

      I still don't get how the Calculator can recommend I use 9 DAGs?

       

      Database Copy Configuration  
      Number of Database Copies

      / Server = 4

      / DAG = 36

      / Environment = 324

       

       

      Database Copy Instance Configuration 
      Number of HA Database Copy Instances / DAG

      / Primary Datacenter = 2

      / Secondary Datacenter = 1

       Total = 3

       

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