In the previous article Step by Step guide on how to install Exchange Server 2010 Beta - Part 1, I have gone through on how to prepare and setup Exchange 2010 environment. In this part of article, I will touch on how to setup DAG(Database Availability Group).

DAG is the new features that introduced in Exchange 2010, it has significant improvement in how Exchange handles the HA and make it simple and cost less compare to Exchange 2007.

Now let's start our lab and configure our 1st DAG.

Step 1: Configure your new mailbox server to have 1 x Public LAN and 1 x Private LAN.

a) In "Network Connections", Click on "Advanced" --> "Advanced Settings.."

b) Configure both "Private" & "Public" to use only IPv4 protocol

Step 2 : Install Mailbox role on the server

Step 3: Create DAG Group

a) Open Exchange Management Shell and execute the following command

"New-DatabaseAvailabilityGroup -Name XXX(Any name your want) -FileShareWitnessShare \\XXX(your chose of server)\YYY(File Share Directory) -FileShareWitnessDirectory C:\ZZZ (Physical file directory path)"

Here is the screen capture of the result from both cmdlets and Exchange Management Tools

Step 4: Create DAG network

You have create at least 2 different network for the DAG to perform Client Access and replication. Below are the commands.

Please remember to use different network segments for different DAG network in order to avoid future issues.

New-DatabaseAvailabilityGroupNetwork -DatabaseAvailabilityGroup XXX -Name YYYPUB -Description "Public network" -Subnets xxx.xxx.xxx.xxx/24 -ReplicationEnabled:$False

New-DatabaseAvailabilityGroupNetwork -DatabaseAvailabilityGroup XXX -Name YYYPVT -Description "Replication Network" -Subnets xxx.xxx.xxx.xxx/24 -ReplicationEnabled:$True

Step 5: Add your Mailbox server to the group

a) Open Exchange management shell(local) and execute the following command. ( The remote shell is not working for the version I am using, it will be fixed when RTM or earlier)

"Add-DatabaseAvailabilityGroupServer -Identity XXX(your DAG group name) -Mailbox Server YYY(Mailbox server name) -DatabaseAvailabilityGroupIpAddresses xxx.xxx.xxx.xxx"

The IP address in the command is used as Cluster IP address.

As you notice, I did not configure Windows Failover Clustering Service before carry on with the DAG setup. This is because, in Exchange 2010, the clustering setup will carry on automatically when the DAG configuration detect this component is missing. (refer to the screen capture below). I am really happy that Microsoft take the inactivate to simplify the steps and make configuring HA for Exchange much more easier than before.

Below is the result after you have add your Mailbox server to the DAG group.

You can proceed to add more servers into the DAG.

To check details of the DAG, simply click on the DAG in the management tools and it will show as below.

Once you have added the second server to the DAG, the File Witness Share directory will be created.

Step 6: Create database copy to complete the DAG setup and achieve HA for Exchange

By adding servers into the group does activate the HA by default. You have to manually create a database copy on different server and complete and setup

Execute the following command in the Exchange Command Shell.

Add-MailboxDatabaseCopy -Identity XXX(Database Name) -MailboxServer YYY(target server) -ReplayLagTime 00:10:00 -TruncationLagTime 00:15:00 -ActivationPreference 2

Now with the database copy in place and mounted, it is sure that your user will very much less affected when the mailbox is crushed. :-)

Let me conclude this article with Quiz again.

What was the significant change in DAG that is missing compare to Exchange 2007? Please send your answer to my Twitter @tristonwan (http://twitter.com/trsitonwan) and if you like this article please tweet this.

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