High availability of New Exchange 2013 features (bottom)

In the previous section we mentioned the high availability differences between different versions of Exchange and their pros and cons, as well as the obvious improvements in high availability above Exchange 2013, although Exchange 2013 continues to use the highly available DAG-enabled technologies of the Exchange 2010 ERA. However, in the Exchange 2013 era, the DAG has changed a lot in detail, mainly in the following aspects:

(1) Automatic Database recovery improvements: Most failures can be recovered by restarting the service or restarting the application pool, and two recovery models are available, namely server mode and database schema. Failure of the protocol in server mode causes automatic server-level recovery, and a single database failure in database mode causes the database to recover automatically. To make this feature better, instead of making the system healthier, Exchange 2013 presents three new criteria for defining what state to take for automatic recovery, which is the trigger mechanism, the health of the database copy, and the priority of the Protocol health.

(2) The choice of the best copy: In a DAG environment, we usually have multiple copies of the database, in the event of a disaster, how do we make the database switch to the best copy, before there is no strict standards, in Exchange 2013 introduced in accordance with the Protocol's health state to select the best copy, The health status of the protocol is divided into 4 priority levels, critical, high, medium, and low, each of which is labeled as a health level.

(3) Maintenance Mode: This feature is a new feature that allows us to check the health of the exchange protocol by using the command set-servercomponentstate to switch the server to maintenance mode.

(4) Improvements to the DAG network: increased automatic configuration of the DAG network.

(5) Site recovery: Compared to Exchange 2010, the namespace redundancy is increased, and mailbox is independent of the CAS role (described earlier in Exchange 2013).

(6) Managed availability with enhanced cmdlets.