Host-based data replication has long been key to disaster recovery planning in the midmarket. They just couldn't justify building the duplicate SAN at their DR site that array-based replication required. More recently, server virtualization has revolutionized how the midmarket plans and builds disaster recovery sites by letting them replace the DR site with 3 to 5 hot standby servers that they would have needed five years ago with a single virtual server host.SteelEye's Protection Suite for XenServer combines these two trends, providing replication at the virtual server host that can replicate the data for all or some of the virtual machines running on that host to a remote XenServer host.

While Windows-only replication vendors such as Double-Take Software and CA XOsoft get most of the attention, SteelEye's been plugging away for the past 10 years with synchronous and async replication software for Linux as well as Windows, so running the replication stack on Xen's Linux platform and integrating with Xen's logical volume manager to acquire the data was right up its alley. It also has integrated with XenMotion and the XenCenter console so it can continue asynchronous replication even when virtual machines are XenMotioned from one host to another.

The current release doesn't include automatic server failover or any application-specific recovery features, so admins will have to change IP addresses and otherwise tell their virtual servers they're in a new location at startup.

SteelEye is selling Protection Suite for $2,500/host server running XenServer standard or $4,000 for those running Enterprise or Platinum. It's also offering time-limited licenses for use while migrating servers, starting at $500 for 15 days.

While VMWare has a substantial lead in management tools over Xen and Hyper-V, the ability to run applications such as data replication on the virtual server host could be an advantage in the SME space where VMWare's DR solutions require SAN replication.