Issue link: https://epubs.iltanet.org/i/27653
toolset with Exchange 2010. We hope to provide some insight from our own experience into the benefits and challenges of Exchange 2010’s DAG implementation. CHALLENGES PRIOR TO EXCHANGE 2010 In Exchange 2003, there were few built-in options for site resiliency, especially over lower bandwidth links. We initially contracted MessageOne, a host- based monitoring solution that utilized DoubleTake for replication of the production Exchange server’s configuration and data. We eventually determined that the solution provided by MessageOne didn’t add enough value to justify the high cost of the service. Our second attempt for Exchange site resiliency was through RecoverPoint, a SAN-based service that replicated the production Exchange databases in near real-time with a standby Exchange server at the disaster recovery site. Unfortunately, this solution didn’t offer a cost- effective growth path for e-mail data because of the RecoverPoint licensing structure. Another major challenge with both of these “Exchange 2010 DAG is an replication feature.” improved log HIGH-AVAILABILITY SOLUTIONS The biggest motivating factor in our migration to Exchange 2010 was the ability of the software to detect when an active mailbox server was unavailable, including major corruption of an active database, and its ability to switch over to another database copy with only very minimal interruption to e-mail service. Exchange 2010’s core design facilitates this process by serving all clients (including Outlook) through a Client Access role server. This access method allows Exchange to quickly redirect clients to a new mailbox server without having to restart Outlook. We have frequently used this seamless redundancy to update Exchange and Windows without service interruption. Cost and a previous designs was the lack of a non-disruptive failover in case the primary Exchange server had major hardware failure. Even with the outside host-based monitoring and replication service, we were looking at a 30-minute downtime window (at least) while the services were transitioned and registered. As you might imagine, the thought of this possibility kept us awake at night. So how did Exchange 2010 address these issues? flexible growth path are two other major advantages with the Exchange 2010 DAG over other high-availability solutions. The big gains in savings actually come from the disk I/O reductions in Exchange 2010. Unlike most SAN replication solutions, you can design a remote-site Exchange 2010 server with lower- tier storage. Another major advantage to the DAG design is that it is storage agnostic. It’s important to still size the disks appropriately in case the server needs to take over an active database role, but it gives you increased flexibility with your storage design. www.iltanet.org Exchange 2010 31