It's been said that a server virtualization project is actually an infrastructure redesign project, and certainly in areas related to storage and data protection, the impact can be dramatic both in terms of the volume of data and in the operations to support and protect it. Backup is a particular case in point.

Fundamentally there are two approaches to backup in VMware environments: the first is to mimic the traditional physical server backup approach by installing backup client software on each VM and backing them up individually. The second is to perform image level backups of virtual disks using either VMware's snapshot capability or a third party. More and more, this second method is being enhanced by mounting snapshots to a VMware Consolidated Backup (VCB) proxy server for final backup via a traditional backup application.

Besides the integration and coordination effort required, another important consideration is the increase of the volume of data created by virtual environments. The standard use of configuration templates for creating virtual machines results in numerous cookie-cutter VMs of a particular class that are nearly identical. Backing up and storing the myriad copies of nearly redundant data consumes significant storage, a fact that has certainly not escaped data deduplication product vendors.

There are at least three ways that deduplication technology can be leveraged in a VMware backup infrastructure:

1. For the traditional backup within a VM approach, both EMC's Avamar and Symantec's NetBackup PureDisk offer VMware clients that de-duplicates data within a VM prior to sending it across the network. 2. The storing of aggregated snapshots is, of course, a prime target for de-duplication making NAS storage platforms that offer de-duplication, like Data Domain and NetApp, NEC and Exagrid may be attractive options. 3. Finally, if data is ultimately being backed up via traditional backup applications, VTL platforms that incorporate de-duplication, such as Data Domain, Diligent, FalconStor, HDS, Quantum, Sepaton, Sun and others may be worth considering.

Each approach offers its own benefits and tradeoffs, but, in any case, the opportunity for dramatic data reduction - and therefore dramatic storage savings - will only increase as virtualization continues to expand throughout the enterprise.

Jim Damoulakis is chief technology officer of GlassHouse Technologies. He can be reached at jimd@glasshouse.com.