The only hitch for some IT shops at this point: Marathon's product works only with the Citrix/Xen virtualized server architecture, not marketshare-leader VMware's. Microsoft Hyper-V support is planned at a later date, but no VMware support is on the drawing board, according to Marathon (which cites its ability to get its product to market faster and ensure proper performance with the Citrix/Xen architecture, among the reasons for this decision.)

Where the Software Lives

On a physical server running VMs, the everRun software sits below the virtual machine layer and just above the hypervisor. That's interesting since many tools sit in the VM or in the OS, says Michael Bilancieri, director of products for Marathon. There are several advantages to this approach, he says, including the Marathon software having direct line of sight to I/O activity, so that in case of trouble, the software can redirect application traffic from a VM without the apps going down for users. Also, the product provides agnostic support for any Windows applications and even legacy apps on the VMs, without the need for customization.

Today's everRun VM solution offers component-level fault tolerance (protecting against any I/O failure, such as a dead hard disk). Later this year, Marathon will ship everRun VM Lockstep Option, providing system-level fault tolerance, designed for scenarios where you lose a whole server for any reason, for example, if you lose a building in a fire. This will essentially be an add-on solution to everRun VM, the company says. Customers will be able to set the desired level of protection VM by VM, to keep costs down for VMs that donâ¬"t need the highest level of protection.

© 2009 CXO Media Inc.