Double-Take Software

I’ve fielded a lot of questions from clients about what Double-Take Software can do on x64 systems.  For the record, nearly all of our solutions are supported on 64-bit systems, both from AMD and Intel. We also have limited support for Itanium, though there is a different licensing structure for that, and not all products are supported; so check with your Double-Take Rep on that one.

As for the x64 architectures, Double-Take can replicate, fail over and even use the DTAM, FFO and SRO wizards between any two x64 machines.  We also have a limited ability to mix and match with x86 servers.  For obvious reasons, the system-state tools (FFO, SRO) won’t allow for this, but Double-Take can replicate data from an x86 server to an x64 server and vice-versa.

Does this mean you can use non-system-state failover between x86 and x64?  That depends on the application in question.  File servers, for example, can fail over from one to the other, though the DTAM wizard would not be used in that case.  I also haven’t heard of SQL servers having an issue in making the jump from one to the other.(Thanks to fellow blogger Nick S for that info)  Many other applications will fall on either side of the equation, check with your application vendor to see if the data from x86 can be mounted/used on x64 or vice-versa.

Exchange is – as usual – a notable exception to that rule.  Since Exchange 2000/2003 won’t run on x64, and 2007 can’t run on x86 (in production), and the database formats are not clearly compatible, this would be one sure case where you would not want to try to replicate between the two with Double-Take.  However, we can protect each of those versions to another server running the same version.  So, use Double-Take to protect the old server before and during the migration, and to protect the new systems during and afterward, just don’t try to use us to perform an Exchange migration.