We are running Exchange 2010 SP2. We have two Data Centers - London and Paris. At the moment, the FSW is listed in London. I understand it's possible to configure an Alternative FSW...but I can't see much documentation on how this works? Will this come into place if the original FSW is down, automatically?

No, it is not automatic and does not provide redundancy. See: http://blogs.technet.com/b/exchange/archive/2011/05/31/exchange-2010-high-availability-misconceptions-addressed.aspx Misconception Number 1: The Alternate Witness Server (AWS) provides redundancy for the Witness Server (WS) The actual name Alternate Witness Server originates from the fact that its intended purpose is to provide a replacement witness server for a DAG to use after a datacenter switchover. When you are performing a datacenter switchover, youre restoring service and data to an alternate or standby datacenter after youve deemed your primary datacenter un-usable from a messaging service perspective. Although you can configure an Alternate Witness Server (and corresponding Alternate Witness Directory) for a DAG at any time, the Alternate Witness Server will not be used by the DAG until part-way through a datacenter switchover; specifically, when the Restore-DatabaseAvailabilityGroup cmdlet is used. The Alternate Witness Server itself does not provide any redundancy for the Witness

No, it is not automatic and does not provide redundancy. See: http://blogs.technet.com/b/exchange/archive/2011/05/31/exchange-2010-high-availability-misconceptions-addressed.aspx Misconception Number 1: The Alternate Witness Server (AWS) provides redundancy for the Witness Server (WS) The actual name Alternate Witness Server originates from the fact that its intended purpose is to provide a replacement witness server for a DAG to use after a datacenter switchover. When you are performing a datacenter switchover, youre restoring service and data to an alternate or standby datacenter after youve deemed your primary datacenter un-usable from a messaging service perspective. Although you can configure an Alternate Witness Server (and corresponding Alternate Witness Directory) for a DAG at any time, the Alternate Witness Server will not be used by the DAG until part-way through a datacenter switchover; specifically, when the Restore-DatabaseAvailabilityGroup cmdlet is used. The Alternate Witness Server itself does not provide any redundancy for the Witness

Hi Redman, Any updates?Frank Wang TechNet Community Support