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Redistributing Database copies in Exchange 2010 DAG

Today let’s discuss about redistributing Database copies in Exchange server 2010 DAG.


Below are the steps to performed


  1. Move away all active copies on that DAG member;
  2. Prevent copies from activating on that DAG member;
  3. Perform maintenance, e.g. down or upgrade DAG member;
  4. Enable possible activation on that DAG member again;
  5. Optionally redistribute database copies.


To make the above procedure  easier and automated regarding moving, activation (un)blocking database, additional scripts are available since SP1 for Exchange 2010.

These scripts are located in the Scripts folder, below the Exchange installation folder. By default the location of the scripts will be C:\Program Files\Microsoft\Exchange Server\v14\Scripts.


Going into Scripts folder directly run the below command


Cd $exscripts it will directly locate to scripts folder



Utilizing them, the procedure is quite easy as you can see below. Note that the example uses a DAG named DAG1 with nodes EX01 and EX02 as members. They both host 11 databases, EX01-DB01 and EX02-DB02; both host 1 active copy and a passive copy of the other database.


1: Login to DAG Member EX01

2: Run StartDagServerMaintenance.ps1 targeting that DAG member,

e.g.:   .\StartDagServerMaintenance.ps1 –server ex01




3: Perform maintenance;

4: Run StopDagServerMaintenance.ps1 targeting that DAG member, e.g.:
.\StopDagServerMaintenance.ps1 –server ex01



5: Optionally run RedistributeActiveDatabases.ps1 for the DAG,


.\RedistributeActiveDatabases.ps1 –DagName EXDAG01 –BalanceDBsByActivationPreference –Confirm:$false






Note: when upgrading on major levels (SP1 to SP2, SP2 to SP3), you can’t move a database to a lower level host. This means that when upgrading a node from SP2 to SP3 and moving a database to that SP3 node in the process, you can’t move that database to any SP2 nodes in the DAG. Keep this in mind when planning your upgrade, because it will impact the availability level by limiting your fallback options.





MCTS,MCITP | Exchange Server

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