Six months ago, two potential customers contacted high availability and disaster recovery vendor SteelEye Technology Inc. of Menlo Park, Calif., with a request: Port your replication software to Citrix Systems Inc.'s Xen, the virtualization technology to which these customers were considering porting their mission-critical applications.
Regardless of the platform an organization chooses, virtualizing an environment augments the need for high-availability software, argued Bob Williamson, SteelEye senior vice president of product management. "The remaining servers after you do a consolidation are really critical resources," he said. "If one of them experiences a problem, many more of your resources are at risk."
SteelEye Protection Suite for Citrix XenServer provides synchronous or asynchronous replication of any running XenServer virtual machine (VM), across a LAN or WAN. The replication engine runs from Domain 0 (Dom0) -- XenServer's console layer -- and offers full support for XenServer resource pools (that is, administrators can replicate groups of VMs as they see fit).
These capabilities stand in contrast to those available with SteelEye for VMware, which can run only from inside a guest operating system and only replicates application-level data. With older versions of ESX, SteelEye was also able to replicate data from inside the service console, but with the current ESX 3.5, VMware has locked down the service console.
"VMware is pushing its replication partners to use its [VMware Consolidated Backup] interface, which doesn't support real-time replication – only snapshotting," Williamson said. VCB 2.0, which should appear next year, is rumored to add support for real-time replication.
SteelEye Protection Suite for Citrix XenServer also features full integration with XenMotion live migration and XenCenter management. Through XenCenter, for example, SteelEye can detect where XenMotion has moved a given VM, and administrators can use XenCenter to start or suspend VMs at a remote disaster recovery location. Williamson also anticipates that customers will use SteelEye Protection Suite as a data migration tool. As such, the company has devised two pricing models.Customers that want to use the Protection Suite for onetime migration of virtual machines can purchase a time-limited license for either 15 days ($495) or 90 days ($1,495). For customers that wish to use SteelEye for continuous replication of VMs, SteelEye offers a permanent license that supports an unlimited number of VMs per XenServer host. SteelEye pricing is set at $2,495 for XenServer Standard Edition and at $3,995 for XenServer Enterprise or Platinum Edition.