Vote for Sonasoft SonaSafe
Sonasoft offers a solution which provides an integrated data protection, high availability and disaster recovery solution for Exchange and SQL servers. SonaSafe application supports many disaster recovery scenarios for virtual servers. Customers can have multiple physical servers at the primary location and at the offsite disaster recovery location; they can have one physical server with multiple virtual servers. Also, multiple virtual servers from the primary site can be backed up and replicated to the disaster recovery site.
In the case of SonaSafe, both on physical and virtual servers, the appropriate agents are installed and these agents have a very small footprint. Because of the limited footprint, the impact on these servers is minimal from a performance perspective. With other replication solutions, one has to install the entire application on the virtual servers and this will take a huge toll on performance.