First Customer Ship (FCS) for Double-Take Availability for Windows (DTAW) 5.3 is out, and with it there are many great feature sets that users can take advantage of. Over the next few weeks, I’ll be detailing some of these.
First up – one near and dear to my own heart as an Exchange Server subject matter expert – expanded support for Exchange Server 2010. 5.2 allowed for Full Server Fail Over support for single-server configurations of Exchange 2010, but didn’t permit the protection of DAG-enabled solutions. FCS 5.3 brings not only multi-server configuration support, but also DAG support for more flexibility in your organization.
Database Availability Groups (DAG) is a new technology in Exchange 2010 that replaces Windows Failover Clustering for local high-availability of Exchange mailbox services. Multiple copies of the mail databases are housed on multiple servers, allowing for server and storage failures to be overcome. We’ve been doing this for years with the GeoCluster tool-set, so we know it works well. It doesn’t, however, work great over a WAN link. To be clear here, DAG will function over a WAN, but without robust bandwidth, it will have issues.
DTAW is designed to run over a WAN without trouble, and to handle things like link hiccups and other normal interruptions between sites. It isn’t uncommon to see clients use Windows Clustering at their production sites, and DTAW to replicate and failover to another physical location when necessary. In much the same way, clients can now create DAG protection groups at their primary locations, and use DTAW to replicate the data and provide a failover pathway outside of DAG to a secondary physical location. This is done without interfering with how DAG operates on the production servers, allowing both technologies to operate side-by-side.
Of course, we also support protection of a single server to another single server, and multiple combinations of physical and virtual devices on either side. But the addition of DAG support allows us to resume our history of protection of production clustered Exchange Servers to a secondary site.
Filed under: Exchange, Vision:101
