Exchange 2010 High Availability Misconceptions Addressed

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We just published a blog post I wrote about some common Exchange 2010 high availability misconceptions that I heard repeated at Tech.Ed North America.  In it, I discuss and dispel several misconceptions:

  • Misconception Number 1: The Alternate Witness Server (AWS) provides redundancy for the Witness Server (WS)
  • Misconception Number 2: Microsoft recommends that you deploy the Witness Server in a third datacenter when extending a two-member DAG across two datacenters
  • Misconception Number 2a: When I have a DAG with an even number of members that is extended to two datacenters, placing the witness server in a third datacenter enhances resilience
  • Misconception Number 3: Enabling DAC mode prevents automatic failover between datacenters; therefore, if I want to create a datacenter failover configuration, I shouldn’t enable DAC mode for my DAG
  • Misconception Number 4: The AutoDatabaseMountDial setting controls how many log files are thrown away by the system in order to mount a database
  • Misconception Number 5: Hub Transport and Client Access servers should not have more than 8 GB of memory because they run slower if you install more than that
  • Misconception Number 6: A Two-Member DAG is designed for a small office with 250 mailboxes or less

Enjoy!