We have two site which are production and DR sites. I was planning to put two DAG members at the production site and one DAG member at DR site. Will this spport? or Do I have to put 4 DAG members in one DAG?
Will the DAG need at least 4 members(or even numbers) ? No. DAG requires minimum one Exchange Member Server. It supports 16 memebers at the max. 2 Member Server in Production Site + 1 in DR Site = 3 Member servers DAG is Supported. Its not mandatory to place 4 DAG members in the DAG.
While 4 nodes are not required you may see it suggested for a couple reasons.
1. Folks who want to go with JBOD for storage. If you do not have at least 2 copies of each DB in a datacenter (and at least 3+ copies of each DB total across all datacenters) then Microsoft recommends sticking with RAID in that datacenter.
2. To enable you to perform intra-datacenter switchovers/failovers without affecting any of the ancilliary functions like CAS/HUB/etc...Brian Day, Overall Exchange & AD Geek
MCSA 2000/2003, CCNA
MCTS: Microsoft Enterprise Server 2010, Configuration
MCITP: Enterprise Messaging Administrator 2010
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