Quoting from Byte and Switch:
Replicating data on virtual servers from the likes of Microsoft and VMware can force users to install multiple servers to accommodate each instance of a virtual-server application (for instance, SQL Server, Exchange, etc.). Not all products can replicate virtual servers remotely. And user-friendly pricing packages that don’t force users to pay for multiple copies of a replication package have been thin on the ground.
It’s important to note that while several products today support data replication of virtual machines on a SAN, we’re talking here about replicating from server to server. And so far, there have been few direct product fixes for the complications involved.
But several firms, including Datacore, NSI Software, and XOsoft are making headway. Next Monday, NSI Software will start shipping Double-Take for Virtual Systems, a product that replicates data from one Windows-based virtual server to another. Users have the option of replicating individual virtual machine applications like Exchange or SQL Server to one or more remote servers. Alternatively, they can replicate the entire virtual-machine server and enable failover in case of disaster…
Read the whole article at source.