Exanet Dips Toe in CDP Pool

Exanet is preparing to incorporate continuous data protection (CDP) into its clustered NAS file system.

Exanet CEO Rami Schwartz says ExaStore CDP will be available in September as part of its ExaStore enterprise NAS platform. ExaStore CDP will be built into the file system and customers can activate it through a license key. Pricing has not been set.

While data protection vendors such as Symantec and XOsoft have built CDP or near-CDP into their software products, Exanet will likely be the first to integrate it into its enterprise NAS file system. (See Microsoft and Symantec Cut SMB Tape and XOsoft Hits Rewind.) Network Appliance acquired CDP technology when it bought Alacritus last year but hasn't yet rolled out a CDP product or given a timeline for delivering one. (See NetApp Annexes Alacritus.) NetApp does support snapshots up to a minute apart on its NAS systems. EMC's RecoverPoint CDP product works with its Legato backup but is not part of its Celerra NAS platform. (See EMC Pulls Forward With Backup and EMC Coughs Up for Kashya.)

"Deploying CDP on a clustered, distributed, file-system platform is a complex and difficult task," Schwartz says, when asked when he expects competitors to follow.

According to Schwartz, ExaStore CDP will capture block-level incremental changes of data by letting users take unlimited snapshots. If data is lost or a file corrupted, users can go back to the last good version. CDP purists will argue this is near-CDP because it relies on snapshots and does not let users restore to any point in time. Exanet calls it CDP because the snapshots can be taken seconds apart.Analyst Arun Taneja says Exanet's approach will be sufficient for many customers, if it lives up to its promise of allowing unlimited snapshots without a performance hit. Taking constant snapshots doesn't do much good if it brings customer systems to a crawl.

"Rapid snapshots are beneficial because not everybody needs constant replication," Taneja says. "If it's a high-end database, the ability to revert back to a second ago has significantly more value, but with standard, run-of-the-mill documents, it's not that crucial to get back to a second ago. But the only way it makes sense is if they solved the degradation problem."

ExaStore CDP does not work with Microsoft Exchange or databases, two of the most common uses for CDP. Schwartz hopes the CDP option will appeal to customers like post-production shops, designers, and manufacturers who work with frequently changed files.

Although Exanet uses snapshots, Schwartz says, it does not capture the entire file that has changed. "Our file system takes snapshots of all files that have been changed since the last time, but we are not keeping a copy of the file," he says. "We keep only the blocks that have been changed -- we just keep the delta. That limits the data we keep to a bare minimum."

At least one of Exanet's 50 or so customers is interested in checking out its CDP. Data Storage Corp. (DSC), an offsite data-vaulting service provider, protects customer data by replicating from its Westbury, N.Y., data center to a Florida site. DSC VP of development Gino Civale says he'll use CDP if it improves the process."Retrieval of data is important," Civale says. "We cannot have any down time. If our service is interrupted, we'll be out of business."

Civale hasn't tried the CDP feature yet, but he says Exanet has kept all of the performance and installation promises it made when he switched over from EMC Celerra three months ago.

"Of course we were concerned about going with a small company," he says. "We made sure to verify everything first. My tech guys were satisfied and everything's gone smoothly."

Dave Raffo, News Editor, Byte and Switch