CDP poised to replace traditional backup methods

Ezine

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We've witnessed major changes in data management during a decade of SAN evolution. Advances in disk capacity, huge reductions in the cost of disk and ever-developing tools have significantly changed the way data is managed. Today, we're able to provision and allocate storage online, create snapshots and local volume copies automatically, and replicate data across long distances. The technologies used to perform these tasks are far from "bleeding edge," but many have been widely adopted and are generally accepted as best practices for managing and protecting data.

Compared to the pre-SAN era, the shift is quite dramatic. But amid this data management revolution, backup is a notable exception. Despite advances such as SAN-based shared tape drives and disk technology like virtual tape libraries, the backup process is fundamentally the same as it was 20 years ago. Backup remains a costly and highly intrusive batch operation that's prone to error and consumes an exorbitant amount of time and resources.

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Defining CDP
    "Continuous data protection (CDP) is a methodology that continuously captures or tracks data modifications and stores changes independent of the primary data, enabling recovery points from any point in the past. CDP systems may be block-, file- or application-based and can provide fine granularities of restorable objects to infinitely variable recovery points."

    --From the SNIA Data Management Forum CDP Special Interest Group


Based on this definition, products like Microsoft Data Protection Manager (DPM) and other snapshot-based solutions aren't technically CDP because they're not continuous--they don't immediately store every change. But if you view data recovery as a continuum with nightly backups at one end of the scale and true CDP at the other, snapshot management tools must be viewed as dramatic enhancements to recoverability. Each environment has specific recovery needs--for those currently dependent on backups, DPM represents a leap forward despite falling short of the CDP ideal.

I'm not suggesting there aren't well-run backup operations. Many organizations have invested in technologies and staff to make their backup process function as effectively as possible. What I am suggesting is that it may be time to step back and rethink the backup process itself. Does it still make sense or can it be replaced by something better?

The emerging technology lifecycle
Technologies exist today to replace traditional backup and to effectively eliminate the nightly backup cycle. It's possible to provide data protection in an integrated and transparent manner without the invasiveness of nightly backups. This can be accomplished in a number of ways. More importantly, it can be done affordably.

I'm referring to continuous data protection (CDP) and snapshot-based CDP-like products that have emerged in the market. Perhaps the greatest promise of these products is their ability to shift the focus of data protection from backup to where it should be--recoverability.

Although quite promising, these products aren't considered part of the data protection mainstream yet. All new technologies face hurdles, but the adoption curve here, compared to VTLs for example, seems to be particularly long. At what point does a technology evolve from "emerging" to "arrived"? The ultimate metric is the number of adopters, but that begs the question, "What compels people to become adopters?" Here are some considerations:

  • The technology must provide significant benefits over current approaches
  • There must be multiple vendors of the technology
  • The adoption risk can't be too high

This was first published in November 2005

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