Double-Take adds replication for virtual machines

By Ann Silverthorn

—Double-Take Software recently introduced new software designed to protect virtual machines in VMware ESX environments. Double-Take for VMware Infrastructure can replicate data from one ESX server to another. This announcement follows the company's launch of Double-Take for Virtual Systems about a year ago.

The replication software integrates with users' existing VMware software. Administrators can select which virtual machines they want to protect and do not have to deploy new software on their ESX servers or virtual machines.

Double-Take for VMware Infrastructure installs on its own stand-alone server and then manages the protection for the selected virtual machines. The software protects operating systems, applications, and data. The virtual machines are not restricted to running Windows; they can run other operating systems such as Solaris or NetWare. The new software contains features found on the original Double-Take software, such as compression and the ability to configure replication frequency.

Regularly capturing changes, Double-Take for VMware Infrastructure keeps the target virtual disks up-to-date and ready for fail-over, recovery, and backup. During an outage, the replicated virtual machine can be started on the target server with the latest replicated data available.

Double-Take for VMware Infrastructure requires that customers have VMware ESX Server version 3 and VMware VirtualCenter version 2, which are the two latest major revisions of VMware.

"We're leveraging VMware's snapshot capabilities," says Bob Roudebush, director of solutions engineering at Double-Take. "VMware has the capability to put a virtual machine in snapshot mode. This means changes to the disk files are frozen and all of the changes are tracked in a delta file that keeps track of those changes. We replicate those changes from one ESX server to another."

Roudebush says Double-Take complements what VMware is doing in terms of VMotion and VMotion HA, because it extends protection capabilities across the WAN. "VMotion is limited to ESX servers that are connected to the same SAN or LAN," says Roudebush. "Double-Take replicates those virtual machines to a different site for disaster-recovery purposes."

A $2,495 license protects up to 10 virtual machines.

This article was originally published on February 26, 2007