Cross Site Dag setup questions. (Full Version)

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pcking999 -> Cross Site Dag setup questions. (13.Apr.2012 12:14:53 PM)

I am migrating from exchange 2003 to Exchange 2010. I am planning a design for the mailbox role like this

Primary AD Site contains:
ExchangeA - Dag is Active
ExchangeB - Dag is Passive

DR site contains:
Exchange C - Dag is Passive

I know that in order to maintain quorum at least 2 servers must be online. If ExchangeA is holding the databases and Exchange B and C go down quorum will be lost. Does that mean that the active databases on Exchange A will shut down, even though they are already active or will exchange see that they are active and continue service requests? I understand the needing 2 servers for failover but will losing 2 passive nodes stop the currently active one from working. I guess my question is does losing quorum mean that just failover stops work or the entire dag does offline and no one can get to the mailboxes even if the active node is fine.




jveldh -> RE: Cross Site Dag setup questions. (11.Jun.2012 9:16:41 AM)

Hi,

Yes if quorum is lost all databases will be brought down, just like a cluster.
Have a look at this article which describes how the quorum is determined etc:

http://technet.microsoft.com/en-us/library/dd979799.aspx

You do although have an option to bring the DAG in the air again but this requires some administrative actions.

Regards,
Johan




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