Issue link: https://epubs.iltanet.org/i/27653
Exchange 2010 also provides scalable growth options. When installing Exchange 2010, it’s not necessary to install it with the special clustering option, which allows you to add the server to a DAG at a later date, without reinstalling Exchange. You can also add up to 16 servers to a database availability group, as needed, giving you maximum flexibility on site placement of servers and active mailbox load-balancing. The final piece that makes Exchange 2010’s DAG a great high-availability solution is ease of administration. You can manage all of the maintenance tasks related to DAG within the Exchange Management Console or Exchange Management Shell — no Windows cluster management experience required! Considering all of these advantages, what’s the most important factor in a successful implementation of Exchange 2010 database available groups? A SUCCESSFUL DAG IMPLEMENTATION In a word (or three): planning, planning, planning. Among the main factors to consider if you want to have a successful Exchange 2010 DAG implementation are: • Software requirements • Disk design • Witness server selection • Active Directory requirements • Network configuration 32 Exchange 2010 ILTA White Paper alternate witness server at “Configure an your disaster recovery site.” Even though the traditional Windows cluster management interface isn’t used to administer the Exchange 2010 DAG, it still uses some of the cluster components for its operation. This requirement means that the Enterprise edition of Windows 2008 64-bit is needed for all DAG member servers. Fortunately, you can upgrade an existing Standard edition install of Windows 2008 to the Enterprise edition with just a license upgrade. Finally, Exchange 2010 Standard edition (and above) is fully supported for DAG member servers. The next planning consideration for an Exchange 2010 DAG implementation is disk design. The path for each database copy must match on every DAG member hosting a replica. Therefore, if you put public folder replicas or other storage utilization functions on a DAG member server or potential member, you must carefully consider the volume layout to ensure compatibility with future database copy needs. A witness server is only required when there are an even number of members in the DAG. Also, it cannot be a DAG member server. The witness server satisfies the majority requirement for a quorum in a DAG (or the DAG will fail) and should be placed at the primary site. You should also configure an alternate witness server at your disaster recovery site in case of a major event at the primary data center. Active Directory design will also have a big impact on the flexibility of your Exchange 2010 DAG design. Every Exchange 2010 DAG member server must be a part of the same domain, but can be in different sites.