Backing up virtual servers ain't what it used to be, and that's good news for server admins For those of you who haven’t made the leap to server virtualization yet, or who are moving from prototype servers to enterprise-critical applications on virtualization platforms, note that backing up VMware virtual servers presents some unique challenges. Although it’s relatively easy to copy the .vmdk file that represents the VMware virtual machine’s boot image, doing so while the VM is running is an accident waiting to happen. Furthermore, standard backup applications treat the VMware instance as a standard OS running on a normal system, which means that a restore won’t work correctly because the backup application tries to restore to a standard hardware system. What’s needed is a backup application that ties into the VMware Consolidated Backup framework. VCB allows for a proxy backup server that offloads the backup processes to a separate dedicated backup server, which can improve performance and reduce loads on the server. [ See the Test Center’s review of high-availability and disaster recovery solutions for virtualization environments, including DataCore SANmelody, Marathon Technologies’ everRun VM, Scalent V/OE, Stratus Technologies’ Avance, and Vizioncore vRanger Pro. ] Many vendors including CA, CommVault Systems, EMC, IBM (Tivoli), IdealStore, Symantec, and Vizioncore have products that work with VCB, but with varying degrees of functionality. Also, admins may need to run both VCB-based full backups for disaster recovery and file-level backups to restore files for users, and overlapping the two kinds of backups could cause a number of problems, from file locking issues to excessive loads on the server. In addition, if the backup software is not sensitive to the applications running on the VMware instance, open files such as databases or Exchange stores could cause trouble, especially since these applications normally run 24×7. The good news is that a number of the backup vendors are releasing second-generation, VCB-capable software. These latest versions offer the ability to back up both the VMware ESX host and all virtual machines running on the server, either over the SAN or via an Ethernet network. They also promise easier configuration for VCB, the ability to back up both virtual machines and files on the guest OSes in a single pass, better reporting, application monitoring, and integration with other virtualization environments including Xen and Microsoft’s Hyper-V. Finally, often licensing is per virtualization host rather than per guest OS instance, reducing overall costs. These backup and restore applications can even lower disaster recovery costs, and ease migration from physical to virtual environments, by backing up a physical server and restoring it to a virtual machine.