70-663 · Question #202
A corporate environment includes Exchange Server 2010 SP1. The Exchange Server environment includes one Hub Transport server, one Client Access server, and one Mailbox server. You are designing an…
The correct answer is A. In the secondary datacenter, deploy one server with the Hub Transport, Client Access, and C. Enable datacenter activation coordination (DAC) mode. One of the great changes in Exchange 2010 over Exchange 2007 is the ability to combine both CAS & Hub roles on mailbox servers configured as DAG DAC mode is used to control the startup database mount behavior of a DAG. When DAC mode isn't enabled, and a failure occurs that…
Question
A corporate environment includes Exchange Server 2010 SP1. The Exchange Server environment includes one Hub Transport server, one Client Access server, and one Mailbox server. You are designing an infrastructure for a secondary datacenter that will provide site resiliency for the primary datacenter that contains the existing Exchange Server environment. You have the following requirements:
- Ensure that employees can access email if the primary datacenter
fails.
- Ensure that each Mailbox database is active in only one datacenter at
a time.
- Minimize the number of Exchange servers required.
You need to recommend a solution that meets the requirements. Which two actions should you recommend? (Each correct answer presents part of the solution. Choose two.)
Options
- AIn the secondary datacenter, deploy one server with the Hub Transport, Client Access, and
- BIn the secondary datacenter, deploy one server with the Hub Transport and Client Access
- CEnable datacenter activation coordination (DAC) mode.
- DDisable datacenter activation coordination (DAC) mode.
How the community answered
(21 responses)- A71% (15)
- B10% (2)
- D19% (4)
Explanation
One of the great changes in Exchange 2010 over Exchange 2007 is the ability to combine both CAS & Hub roles on mailbox servers configured as DAG DAC mode is used to control the startup database mount behavior of a DAG. When DAC mode isn't enabled, and a failure occurs that affects multiple servers in the DAG, when a majority of the DAG members are restored after the failure, the DAG will restart and attempt to mount databases. In a multi-datacenter configuration, this behavior could cause split brain syndrome, a condition that occurs when all networks fail, and DAG members can't receive heartbeat signals from each other. Split brain syndrome can also occur when network connectivity is severed between the datacenters. Split brain syndrome is prevented by always requiring a majority of the DAG members (and in the case of DAGs with an even number of members, the DAG's witness server) to be available and interacting for the DAG to be operational. When a majority of the members are communicating, the DAG is said to have quorum.
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