EMC adds snapshots, hints at CDP

Posted on September 22, 2005


By Ann Silverthorn

—EMC this week introduced snapshot support for RepliStor 6.1, a data-replication product brought into its portfolio from the Legato acquisition. EMC claims 20,000 customers use RepliStor. The enhancement supports Microsoft Volume Shadow Copy Service (VSS), enabling users to create and recover multiple point-in-time copies of file system and application data.

Traditionally, RepliStor has competed with products such as NSI Software's Double-Take, but with the latest version EMC claims that RepliStor will now compete more directly with Microsoft's Data Protection Manager (DPM) and Symantec's upcoming "Panther," both of which EMC (and others) refer to as "near" continuous data protection (CDP).

EMC confirmed plans to announce a separate CDP product at the Storage Networking World conference in October.

"We look to the SNIA definition that focuses on fine-grain recovery," says Rob Emsley, EMC's director of product marketing. "Customers are looking for finer-grain recovery at a better recovery time objective (RTO). CDP requires continuous capture of all data changes and the ability to expose those data changes at any point in time."

The Storage Networking Industry Association's CDP special interest group defines CDP as follows: "Continuous data protection 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."

"CDP is an architecture that captures every change in the production environment down to the transaction level," Emsley continues. "From there, you can add integration with applications, such as databases. It is not just file-based integration."

RepliStor, which EMC underscores is not CDP, delivers real-time asynchronous replication from various combinations of Windows servers: One-to-one, one-to-many, many-to-one, many-to-many, etc. The product's replication ability for content distribution or disaster tolerance has been available for a few years, according to Emsley. If one server went down, operations could be continued from a restart of the other. With the 6.1 support for consistent snapshots, users now have the added ability to recover to a previous point in time.

RepliStor is priced at $1,650 per server. Approximately 80% of RepliStor shipments go through EMC's channel partners.

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