Microsoft Exchange Server 2010 provides us lots of tools for failover redundancy (in case of server failure) and load balancing (distributes traffic between servers). In this article, we will try to know a little bit about on these methods to get an idea of them:-
1. High Availability and Site Resilience
Exchange Server 2010 offers us Database Availability Groups (DAGs) where we can deploy two Active Directory sites in two different locations, and keeping their mailbox data synchronized. In case one site fails, other site will take over its role. We can achieve high availability by configuring up to 16 mailbox servers for automatic recovery without installing any new servers. DAGs provides us local and site-level high availability.
2. Online Mailbox Move
We can now move the mailboxes whilst the users are logged in. This is only possible if source mailboxes are residing on Exchange Server 2007 SP2 or later, or Exchange Server 2010. It will give users the continuous access to their mailboxes while their mailbox is in the moving process.
3. Shadow Redundancy
It protects the messages when they are in the deletion process. Before they are actually deleted from the transport database, the transport server first verifies that all the next hops for the message have been completed. If next hop is not completed, the message is resubmitted for delivery to the next pending hop. This is very similar to Transport Dumpster. In shadow redundancy, the source server will delete the shadow copy of the message after it receives the discard status notification from the next hop.
4. Load Balancing
As the name suggests, it provides balancing of network load or traffic across different servers. Unlike previous Exchange versions, where Mailbox servers were directly connected with the Outlook, Exchange Server 2010 Client Access Server is now used for connecting internal or external Outlook connections.