How to: Database Availability (DAG) Group in Exchange 2010

A cool new feature in Exchange 2010 is the Database Availability Group (DAG). With this feature you can put a copy of your mailbox database on multiple mailbox server (max 16.). The Database Availability Group uses the Windows Failover Clustering feature and you can manage everything through the Exchange Management Shell (EMS) and the Exchange Management Console (EMC). Let’s have a look on that…

This is my Exchange 2010 environment:

Server 1 – SRV-EXDC-01
Microosft Windows 2008 R2 Enterprise x64
Roles: Active Directory, DNS

Server 2 – SRV-EX10HT-01
Microsoft Windows 2008 R2 Enterprise x64
Roles: Exchange 2010 HT/CAS

Server 3 – SRV-EX10MB-01
Microsoft Windows 2008 R2 Enterprise x64
Roles: Exchange 2010 MBX

Server 4 – SRV-EX10MB-02
Microsoft Windows 2008 R2 Enterprise x64
Roles: Exchange 2010 MBX

1.) First I’ve created 2 new mailbox database on each mailbox server.
SRV-EX10MB-01 – MD01, MD02
SRV-EX10MB-02 – MD03, MD04
2.) The next step is to create a new Database Availability Group.
Witness Server: SRV-EX10HT-01 (Could also be a another server, but not a member of the DAG!!)
Witness Directory: C:\FSW_DAG01
3.) After succesfully creating the DAG, we can added some mailbox servers to it
SRV-EX10MB-01 and SRV-EX10MB-02
4.) The Windows Failover Clustering feature will automatically installed on each Mailbox server
5.) Give the Database Availability Group an IP address. This can be done with the following command:
Set-DatabaseAvailabilityGroup -Identity DAG01 -DatabaseAvailabilityGroupIpAddresses
6.) The next step is to add a Mailbox Database Copy
7.) The copy of the Mailbox Database will be copied to the other mailbox server. As you can see, Mailbox Server SRV-EX10MB-02 is now also containing Mailbox Database MD01 and MD02
8.) Login through the Outlook Web App with a user in Mailbox Database MD01
9.) Disable the LAN connection on Mailbox Server SRV-EX10MB-01 (fake a failover!)
10.) You’ll now receive an error in your Outlook Web App, this is normal, because the active mailbox is unavailable!! Wait a copple of seconds and click another e-mail message! As you can see, the passive Mailbox Database copy is now become active!! cool…. 😀
11.) After enabling the LAN connection on Mailbox Server SRV-EX10MB-01, the copy status become Healthy again!
12.) You can also test the “Fail Over” manually. Right click on your Mailbox Database, choose Move Active Mailbox Databse, and select the new active Mailbox Server.

So….after all, a copple of seconds downtime for the users!

DAG_01    DAG_02    DAG_03

DAG_04    DAG_05    DAG_06

DAG_07    DAG_08    DAG_09

DAG_10    DAG_11    DAG_12

DAG_13    DAG_14    DAG_15

DAG_16    DAG_17    DAG_18

DAG_19    DAG_20    DAG_21

DAG_22    DAG_23    DAG_24

DAG_25    DAG_26    DAG_27

DAG_28    DAG_29    DAG_30