Mainframe Killers?
In this case, the "upper end" is the mainframe database market, where IBM remains the undisputed leader (Jones claims his company has more than 98 percent market share). The OS/390 version of DB2 can handle as many as a million simultaneous users, making this a mainframe solution extremely attractive for high volume environments.
When comparing the merits of clusters versus mainframes, however, it's important to account for cost. Clusters let you either add low-cost hardware or repurpose existing hardware to scale your database, instead of buying ever-larger single servers (which can be extremely costly).
Oracle's Ellison insists that an Oracle RAC cluster running on low-cost, commodity hardware is a viable, even preferable alternative to expensive servers or mainframes. "It would be faster than an IBM mainframe, more reliable than an IBM mainframe, at less than one twenty-fifth of the cost," he said.
Whether or not you believe the performance claims, there are likely to be hidden support costs for any clustered database. In the case of shared-nothing architectures like IBM's, growing the database may require manually reapportioning the data across newly added servers. Even Oracle has hardware certification requirements for RAC, so not just any old box will do. If transitioning away from reliance on mainframes is an issue, IBM DB2 UDB may be the database of choice. Although its internals are built using a different architecture than DB2 for OS/390, it still offers strong integration with IBM's mainframe product. Also, because DB2 UDB is built from a single, unified code base for a plethora of OS platforms, it's perhaps the most flexible clustered database solution.
Software and Strategy
That flexibility lies at the heart of IBM's database strategy, and ultimately it may expose the most telling contrast between the two companies. IBM's willingness to support heterogeneous environments extends even to the database software itself. "We don't come into a customer's shop and say, for us to help you, you're going to have to move everything you have onto DB2," Jones explains. "We tell our customers, work with us and we will help you manage the data you have, wherever it is."
While IBM remains committed to being a full-service solutions provider, at heart Oracle remains a software vendor. Little wonder, then, that Oracle consistently encourages migrating data to its own software. "IBM's business is to say, take whatever you've got—this morass, this briar patch of computing—we'll just take it over, and we'll raise your prices," Oracle's Ellison scoffs. To Oracle, standardizing on a single database platform is one of the best ways to lower costs and create efficiencies within your IT infrastructure.
Each approach has gained its converts, and each clustering solution is beginning to see real-world deployment. On the high end, IBM reports that a company called NewTech Sciences is running DB2 on a 1,250-node cluster of Linux servers. Another example is Florida International University, which operates a data visualization application called TerraFly using a 13-terabyte clustered DB2 database.
Oracle, on the other hand, boasts such corporate customers as American Airlines and logistics management provider Vector SCM among its RAC client list. Neither company would comment on its experience with RAC, however, as is often the case with large enterprise software customers. As a result, it's difficult to accurately assess market reaction to these emerging technologies.
Slow Adoption
Rich Niemiec, president of the International Oracle User's Group, predicts increasing interest. "Most people think that they need a super server or terabyte database to need and/or benefit from clustering," Niemiec explains. "When more people understand that clustering is not only beneficial but preferable for even the smallest servers, you'll see implementations on a larger scale."
But some analysts disagree. Gartner Research Director Betsy Burton, for example, has predicted that less than 10 percent of Oracle customers will adopt RAC by 2006, citing the software, hardware, and maintenance investments involved as major limiting factors.
Faced with such skepticism from an analyst of Burton's expertise, even Oracle's Ellison is forced to temper some of his rhetoric. "Even 10 percent would be a phenomenal update," he told reporters at Oracle OpenWorld. IBM's Jeff Jones, meanwhile, thinks Oracle's enthusiasm oversteps reality. "Clustered databases are still a territory of very large customers," he says.
Based on these assessments, the best advice for now is to approach clustered databases with caution. If you already manage an extremely large data store and are reaching capacity on your existing hardware, clustering may provide a welcome alternative to costly single servers. For most applications and environments, however, clustering is not yet a drop-in replacement for stand-alone database servers, despite the hype.
Neil ([email protected]) is senior technology editor for New Architect.
