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When CDP products first appeared a few years ago, the benefits were clear, but implementation and other issues quickly stifled interest. Now CDP is making a comeback, and it might just be the future of data backup.
Continuous data protection (CDP) and related products are the future of backup. There's no question CDP products failed to live up to the hype when they first appeared several years ago. But it's also true that the way CDP was (and is) designed solves virtually every major problem that has plagued backup and recovery systems for decades, and offers recovery time objectives (RTOs) and recovery point objectives (RPOs) that traditional backup systems can only dream of. Current CDP products have also addressed most of the shortcomings the first batch of products had. The CDP buzz may be gone, but the reality of CDP is stronger than ever.
A few years ago it seemed like every other booth at storage trade shows was occupied by a CDP vendor, and a steady stream of technical articles extolled the virtues of continuous data protection. But hardly anybody bought the story or the products. Some pundits even joked that CDP stood for "Customers Didn't Purchase." The failure of continuous data protection was so complete that only two of the original CDP vendors were left standing. The others were acquired by larger companies that believed in the technology enough to buy a product that often had few or no customers.
Why CDP 1.0 tanked
So, if CDP was such a good idea, why didn't anyone buy it? There are several reasons.
First, most of the companies offering CDP were startups. The worry, of course, was that you would invest money, time and energy in a startup and its product only to see the company go out of business. Sadly, those fears were realized in this case: Asempra Technologies Inc., Double-Take Software Inc., FilesX, Kashya Inc., Mendocino Software Inc., Revivio Inc., Storactive Inc. and XOsoft Inc. were all acquired by other companies, and some (although not all) of these acquisitions resulted in very rocky experiences for the few customers who had purchased their CDP products.
Continuous data protection was also a big pill to swallow. While you could technically run a CDP system in parallel with your traditional backup system, very few people had the budget or time to do that. Therefore, you had to justify replacing your production backup system with CDP. But because it was so different from what people were used to, CDP was hard to fully understand and was a hard sell to replace traditional backup.
Another real problem was that the products sometimes weren't fully up to the task. For example, users were often forced to choose between an on-site or off-site copy of their data because most CDP products couldn't deliver both. This meant one product had to be used for operational recovery and another for disaster recovery (DR). Many CDP products were also ignorant of the applications they were backing up. Continuous data protection vendors said they had no more of a requirement to understand applications than a storage array did. Technically true perhaps, but it didn't give users the warm fuzzy feeling they were used to; they wanted a CDP product that was application-aware. CDP also required a lot more storage than traditional backup products or snapshots, so CDP customers were unable to have very long retention periods. This required them to have a separate solution for long-term retention.
This was first published in August 2010