The frenzy over continuous data protection (CDP) reached a fever pitch this fall with several new products on the market. At the same time, shifts in vendor rhetoric suggest they're being more realistic about their products' scope.
It's increasingly clear that there are two kinds of CDP: one for user files and another for enterprise applications. Products catering to the former include IBM Tivoli CDP for Files, Microsoft's Data Protection Manager and Symantec/Veritas' Backup Exec 10d. Enterprise applications, meanwhile, use Asempra Technologies' Business Continuity Server (BCS); CommVault Systems' Continuous Data Replicator, an add-on to its QiNetix data management suite; EMC's RecoveryPoint; and Mendocino Software's RecoveryOne (upon which EMC's product is built).
With the early days of CDP behind us, vendors seem to be playing down the idea of restore to "any point in time" without abandoning the idea altogether.
For example, in addition to recovery to any point in time, EMC RecoveryPoint offers recovery to a "significant point in time"--i.e., the last time the application was quiesced. Unlike snapshot-based products, EMC's and Mendocino's products never stop copying data; rather, they "annotate the CDP timeline" when the application is known to be consistent.
Asempra also takes pains to guarantee that you'll be able to recover your application along with data. By integrating directly with specific applications (Windows file and print, Exchange and SQL Server) and copying data at the transaction rather than block level, "everything is by definition consistent," says Marty Ward, Asempra's VP of marketing and products.
Recovery to a specific point in time, if it isn't consistent with the application, can be "a case of diminishing returns," says Rob Emsley, EMC's director of software product marketing. "While you're trying and trying and trying [to recover], the business is still completely on its back, saying 'Please help me.'"