Installing an Exchange Server 2016 Database Availability Group (DAG)

Introduction

Database Availability Group (DAG) is a high availability and site-resilience framework to Exchange Mailbox server that gives you the capabilities to ensure the availability of your database. Database availability group (DAG) was first introduced in Exchange Server 2010. DAG can support up to Sixteen mailbox servers in a single DAG group. Any server in a DAG can host a copy of a mailbox database from any other server who is member of DAG group.

If you have not installed your Exchange Server 2016 yet, follow the step by step guide to deploy your Exchange server 2016 from here

Installing an Exchange Server 2016 Database Availability Group (DAG)

I am going to install a 2 node IP less DAG in single AD site with a third Windows server in the same site as the file share witness. IP less DAG has no cluster administrative access point (CAAP) and do not support backup application that relay on cluster administrative access point for backup.  To Install an Exchange Server 2016 DAG, follow the steps mentioned below.

  • Login to Exchange 2016 server as administrator
  • Navigate to Servers > Database Availability Groups and click on + icon

Installing an Exchange Server 2016 Database Availability Group (DAG)

  • Specify your DAG name, Witness Server and witness directory and click on Save. As I’m using a 3rd server as Witness server that do not hold any Exchange server service. You need to add “Exchange trusted subsystem” to local admin group on witness server.

Installing an Exchange Server 2016 Database Availability Group (DAG)Installing an Exchange Server 2016 Database Availability Group (DAG)

If you leave the Witness Server field empty, wizard will search for an Exchange 2016 server with Client Access services, and it will automatically create the specified witness directory on that server, share the directory, and configure the DAG to use that Exchange 2016 server with Client Access services as its witness server.

  • Once the DAG group is created, the next step is to add members to DAG. To add member servers, Select the DAG group and click on Settings icon

Installing an Exchange Server 2016 Database Availability Group (DAG)

  • Add member servers to the DAG group

Installing an Exchange Server 2016 Database Availability Group (DAG) Installing an Exchange Server 2016 Database Availability Group (DAG)

  • Your DAG is installed and has 2 member servers added. The last step is to setup DatacenterActivationMode to “DAGOnly”. Run the following Exchange Management Shell cmdlet to set DatacenterActivationMode

Set-DatabaseAvailabilityGroup -Identity Dag01 -DatacenterActivationMode DagOnly

Installing an Exchange Server 2016 Database Availability Group (DAG)Once your DAG is setup. Last step is to add database copies to DAG and distribute your database load on multiple servers.

For more information on Exchange 2016, please go through the following blog posts.