Are Public folder databases supported by DAG?
The answer is no. Unlike CCR where you could protect public folders using continuous replication, with DAG you must use traditional public folder replication mechanisms. It is important to note that nothing stops you from having a public folder replica on an Exchange 2010 Mailbox server that also is a DAG member. Where should I place the Witness server? Well, a general best practice recommendation is to place it in the primary datacenter. That is the datacenter to which all users connect (unless a switch or failover aka *over occurs) or the majority of users connect. There may be exceptions to this, so I recommend you do some research on the topic. A good place to begin is here. I am also working on a multi-part article covering multi-site DAG solutions, which will be released on MSExchange.org in the near future. How long does a switchover or failover take between DAG members? Unlike CCR failovers and switchovers which could take up to a couple of minutes, with DAGs they usually take
