Enter the Hypervisor: the changing face of backup

Remember that first flat-bed scanner you owned? The memory might not be as vivid as with your first car, but chances are you stayed up late at night discovering the joys of scanning old photos and documents. After a while, the realisation hits that this could make saving all those receipts and tax forms a lot easier too. Instead of loading up the cabinet with files of paper documents, you can simply scan and capture an image of the entire mess, easily reproducing some or all of it at a later point in time.
    
IT professionals are making the same kind of discoveries with the multi-faceted benefits of virtualised environments. No longer bound by the restrictions of individual physical servers, systems administrators and managers alike have found all kinds of reasons to embrace the Hypervisor – a clever layer of abstraction that allows entire server farms to be condensed down to a few choice pieces of hardware. The Hypervisor is the technology that virtualises physical hardware assets: the user is none the wiser, and the CIO can deliver significant operations benefits.

Lessons learned
As is often the case, however, the new efficiencies and savings are sometimes realised only after the painful lessons learned by early adopters. New technologies can create difficulties for older software and technologies, which is particularly problematic in systems built to support mission critical functions like data backup. At the beginning of the virtualisation evolution, many pioneers found their existing backup and recovery applications fell short when it came to both protecting and restoring their virtual environments.
    
As backup companies made improvements to their applications to accommodate the new realities of virtualisation, a few forward-thinking innovators began to reconsider some of the unique properties of the hypervisor to create entirely new ways of creating and restoring backups. They started by taking advantage of the fact that a virtual machine is actually a file and can be therefore backed-up more easily than physical systems. Benefits include:
•    The inherent ease in making snapshot images of an entire system
•    The hypervisor’s unique ability to allow users to transfer this system snapshot image to a different piece of hardware
•    The ability to extract a granular hierarchy
    of application objects, such as individual spreadshhets, from the virtual machine image.

By using backup tools that have been built to make the most of these unique characteristics, innovators found that capabilities of virtual environments significantly improved at the same time as reducing manual efforts for system administrators.

A new era for data backup

Scanning for changes remains one of the most prevalent performance problems affecting backup – a seemingly endless cat and mouse game with your file system (“did this or that file change since the last backup?”). This has made traditional backup particularly time and resource hungry.
    
With the computer’s file system now encapsulated into a single file on the host, an image-based backup approach eliminates the old process of file scanning.
    
The hypervisor presents image backup applications with a map of the individual data blocks that make up the entire virtual system. In a fraction of the time needed to scan the file system on physical machines, the backup application can select only those blocks which are active, changed, duplicate, deleted or empty. Using this capability, the backup application can make quick work of reading and transmitting only the necessary blocks to the storage location of choice.
    
Backup administrators also find great advantages in the simplicity of such a virtual environment. A large burden on many administrators is the complex setup and management steps required by multiple backup agents, zones and server equipment required to protect physical environments.
    
Virtualisation can greatly simplify this setup, providing a unified platform for backup applications to collect and analyse the required data. Often, a single instance of an image-based application can protect multiple virtual host servers at once, sending multiple backup streams in parallel, directly to the storage target. Agents and complex server configurations become a thing of the past.

Recovery is just as important as Backup
Because the backup routine happens on a daily basis, while recovery occurs (ideally) much less frequently, the process for recovery may not get the attention it deserves. Here again, a virtualised environment presents unique opportunities for improvement. 
    
A virtual environment can deliver unprecedented flexibility with regards to what is being recovered, the point in time from which it is recoverd, the system to which it can be recovered, and how quickly it can be recovered.
    
Entire data centres can be restored with relative ease, on dissimilar hardware, without pre-staging system configurations and tweaking application-level settings. Individual objects including files and e-mail objects can also be selected and restored. Recovered files can be located back to the original production systems, or be recovered on new systems and at new sites and locations. Entire systems can be rebuilt from bare metal.
    
In short, recovery can be as global or granular as is required, working with the same protected images. This flexibility replaces the need for entire categories of specialty backup tools including bare-metal protection, application-integrated agents and the like. Instead, protection of the virtual system image provides all of the recovery required. This capability is known as Backup Once, Recover Any.
    
So while the hypervisor may not have been created specifically for better backup, for many organisations it offers the secondary benefits of flexibility and saving money. It makes data protection and disaster recovery imminently more efficient; enhancing the prime reason you backup in the first place – to cover your assets.

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