The kind of flexibility true CDP offers brings the VCR -- or TiVo -- rewind capability to mind, making it the ideal data protection safeguard for applications without a safety net, such as e-mail, database updates, word processors, and CAD/CAM. Not surprisingly, a number of lightweight CDP applications on the market protects user files, including what's stored on desktop and laptops. But the heavy lifting of data recovery for many companies revolves around e-mail and database-centered applications.
When considering a CDP solution, however, keep in mind that CDP alone does not provide application recovery. For that, you will need additional software. That said, CDP is an important first step toward ensuring that your data is safe -- and that the lifeblood of your business can easily be restored should something damaging transpire.
Few technologies can claim the quick road to success that data deduplication can. Just four years ago, the technology was proposed by but a few pioneers, largely ignored by major storage vendors. Today it is difficult to single out a vendor that doesn't have a data deduplication slide in its marketing materials.
In hindsight, the quick success of data deduplication is easy to explain: It's the most effective strategy for offsetting a significant portion of the data currently deluging companies. And with some enterprises doubling the amount of data they must manage every year, it's not surprising to see how data deduplication's promise to shrink data capacities by a factor of 20 to 1 would appeal to most.
To achieve that level of capacity reduction, data deduplication technologies use algorithms that essentially replace identical globs of data with pointers to a single instance. Implementations differ in how they apply those algorithms; for example, Sepaton pursues file-based byte-level comparisons, whereas Data Domain looks for equal fragments within files.
Moreover, the size of the fragments replaced can be either fixed or variable, another key differentiator among data deduplication solutions. Avamar, for example, uses a variable-size segment to identify duplicates. According to the vendor, which was recently acquired by EMC, the approach remains effective even when minor changes, such as inserting a single line in a document, could defeat comparisons between fixed-length segments. Despite such comparative claims, however, vendors' declared average deduplication ratios differ very little.
Other differences in how vendors implement the technology can have a more significant impact on the effectiveness of data deduplication in your daily operations. Adding traditional, hardware-implemented compression, for example, can further reduce data capacities by 50 percent -- a nontrivial gain that essentially doubles your dedup ratio.
Putting the dedup magic wand to work in line with your backups may seem the smart thing to do, but only if the added overhead doesn't extend your backup windows into business hours. Because of this, some companies may benefit from a more prudent offline, off-band approach to deduplication.