Wednesday, January 18, 2012

Change DAG Witness Server - Exchange 2010 Hosted

I recently had to change a DAG on Exchange 2010 Hosted. This only uses the Exchange Management Shell, and I couldn't find instructions specific to this, so I thought I'd share my experience.


Witness Server has the following Requirements:

-          Can’t be part of the DAG

-          Same AD forest as DAG

-          Windows Server 2008 R2, Windows Server 2008, Windows Server 2003 R2, or Windows Server 2003

-          Each DAG requires a different witness directory, but they can all be run on the same server


Set permissions on target server –

Local Administrors group – add Exchange Trusted Subsystem

Reboot server to apply permissions


Go to Exchange Management Shell, and type in:

Get-DatabaseAvailabilityGroup | fl

There are two lines to pay attention to: WitnessServer and WitnessDirectory

To change the Witness server, type the following:

Get-DatabaseAvailabilityGroup | Set-DatabaseAvailabilityGroup –WitnessServer witness.serverdomain.local –WitnessDirectory C:\DAG1

Dustin Shaw


  1. I have a good number of employees in my company and I’m looking at investing in a hosted exchange solution for all of them. Can you please tell me how much it will cost, if I have to get email hosting for 100 users? Are they charged on number of accounts or by the amount of data stored?

  2. Thanks! Is easy but never dies.

  3. hi,
    Could the witness share be a NETAPP CIFS ?