Insider: CDP Streamlines Restoral

If your data is lost, how fast can you get it back? That's the question at the heart of developments in continuous data protection (CDP). The speed of retrieval with CDP could justify its downsides, according to the latest Byte and Switch Insider, this publication's paid subscription research service.

To review: While some say CDP is just another word for backup and replication, a small group of emerging players insists that only the ability to pick out a specific point in time, and retrieve data in toto from there, qualifies as CDP.

It may seem like a marketing argument, but it has implications for users and IT managers. According to the report, "Continuous Data Protection: Backup to the Future," it can take much longer to restore data if CDP isn't used.

Virtual tape libraries (VTLs), for instance, usually activate just once a day, which can leave a 24-hour gap if an outage occurs. Snapshots, or images of file system data from a specific point in time, can make restoral more accurate, but administrators have to schedule them, reserve disk space to store them, and hunt through them to find a good version when restoration is needed.

Another alternative, synchronous replication, can take hours and cause performance bottlenecks, leaving more of a protection gap than many companies feel comfortable with.By monitoring write and log I/Os with time-stamps to enable recovery from any point in time, CDP software keeps data loss and restore times to a minimum, the report maintains. But there are drawbacks. CDP is still relatively immature technology that lacks major vendor support. Today, just six vendors, most of them startups, can claim to be shipping products. These include: Mendocino Software, Revivio Inc., Storactive Inc., Topio, XOsoft, and Zetta Systems Inc.

Established players, including EMC Corp. (NYSE: EMC), Microsoft Corp. (Nasdaq: MSFT), Network Appliance Inc. (Nasdaq: NTAP), and Veritas Software Corp. (Nasdaq: VRTS), are in various stages of releasing CDP wares, but none is shipping a product in volume.

Early adopters, however, could find the present CDP tradeoffs acceptable. At the University of New Mexico, for instance, systems specialist Chuck McQuade has scoped out Revivio's CPS 1200 in order to better back up an Oracle-based ERP system. While not live yet, the product will eliminate several awkward steps McQuade now takes to back up data, and it will help him avoid taking the database server down in order to take snapshots. These improvements will clearly save operating costs.

Still, organizations may have capital outlays, including disk-based systems, in order to support full-scale CDP. And a few are likely to balk at the overall newness of the technology, or software costs, which can range from a couple thousand to many hundreds of thousands for a product like Revivio's. Still, faster disaster recovery could balance out these concerns in the right environments.

Apart from the startups and public companies mentioned above, this report examines products from the privately held companies InMage Systems Inc. and TimeSpring Software Corp. Other companies mentioned are: Constant Data Inc., Hewlett-Packard Co. (NYSE: HPQ), FalconStor Software Inc. (Nasdaq: FALC), Kashya Inc., Lasso Logic, Mimosa Systems Inc., NSI Software Inc., Sanrad Inc., and Sun Microsystems Inc. (Nasdaq: SUNW).Mary Jander, Site Editor, Byte and Switch

The report, Continuous Data Protection: Backup to the Future, is available as part of an annual subscription (12 monthly issues) to Byte and Switch Insider, priced at $1,350. Individual reports are available for $900. For more information, or to subscribe, please visit: www.byteandswitch.com/insider