The latest plan for migrating from 2010 to 2013 is to create a new 3 member DAG with all the active mailbox databases on the 2 DAG members inside our office and the 3rd DAG member hosting passive copies in a remote data center.

We want to keep the active database copies on the LAN since most email activity during office hours is generated by Outlook clients on the LAN and having all databases except one of them kept local to the LAN should reduce traffic across the WAN due to less database replication happening.

The DAG member in the data center will also do the additional role of CAS server for remote users accessing their mail from the Internet.

If there is a power outage requiring the all servers in our local office including these two DAG members to all be quickly powered down before UPS batteries die, what is going to happen with a 3 member DAG vs 4 member DAG?

I assume that with a 4 member DAG with FSW in the data center, the databases in the DAG should all become active automatically, but with a 3 member DAG, with a power outage in the office containing two DAG members, we would have to access the data center server using an outside internet connection (mobile data plus VPN etc)  and perform some kind of action to manually activate the databases there.   Is that true?  Anything else to consider about this layout?

We have to weigh the costs of adding an additional server to be the 2nd DAG member in the data center increasing the total multi-site DAG from 3 to 4 members and then also increasing the replication traffic on the WAN in the process vs saving that expense and having reduced replication traffic, but having the longer outage, and extra work to manually activate the passive databases in the data center.

• Edited by MyGposts 6 hours 7 minutes ago