Technology managers seeking to reap the benefits of storage virtualisation are at a crossroads, and two storage industry powerhouses, IBM and EMC, want to take them in very different directions. On Wednesday IBM trumpeted some new customers who are trying its way, and reviewed its case with analysts and press about why other IT departments should do the same.
Experts are not passing judgment on which architecture is right for users, and some caution that until arch rival EMC delivers on its alternative approach and both can be tested, the debate won't be settled.
Virtualisation, the ability to work with logical representations of physical storage, computing and networking resources, is at the heart of the dream of the future data center, according to Arun Taneja, founder of analyst firm Taneja Group. The ability to see and manage data as a single logical resource, regardless of where it physically dwells in the typical company's large and disparate group of storage systems and networks, promises enormous productivity and cost savings to IT, he and others agree.
In seeking to deliver on that promise, IBM can offer users a virtualisation strategy that spans computing and storage, the benefit of its long history offering storage virtualisation tools on the mainframe -- and it can also offer a shipping product, the SAN Volume Controller (SVC). EMC's Storage Router, seen by many as the biggest competitive threat to the SVC, is much discussed but a relative unknown to the market; it's slated to ship in the second quarter of this year.
A key architectural difference between the two products is that IBM's offering is in-band -- it is a controller that sits on the data path between applications and storage resources -- while EMC's is out-of-band. In EMC's case, the router communicates with intelligent switches such as those from Cisco Systems to establish a connection and then the application and storage talk directly, explained Richard Villars, vice president, storage systems research at IDC.
"IBM's approach aims to take the intelligence out of storage arrays," said Villars. "The payoff is a common management scheme. EMC keeps the intelligence out on the arrays, and all you're doing is routing information." However, this approach doesn't help with functions such as data replication, which still requires the addition of software to individual disk arrays, he said.
Taneja thinks that both vendors' approaches are viable, and that in the first round of purchasing, users are likely to be drawn to the offering from the vendor that is already their dominant storage vendor. That would seem to give an edge to EMC, which took 21 percent of the market for external disk storage systems in 2004, compared to IBM's 12.6 percent share, according to IDC estimates. EMC also grew its market share by 18 percent, while IBM lost about four percent of its share.
Users are moving slowly into storage virtualization. For the moment, adopters of IBM's technology number about 1,000. Nearly half of its customers still have no plans to implement it, although they are aware of the technology, Nigel Dessau, IBM vice president for virtualisation solutions, systems and technology, said Wednesday. A smaller number of customers have another component of IBM's virtualization schema, SAN File System.
One of those users is CERN, the European Organisation for Nuclear Research, which on Wednesday announced with IBM that it was seeing good results of internal testing of SAN File System during simulation of the computing needs of the Large Hadron Collider Computing Grid. The grid is expected to produce 15 million gigabytes of data per year when it starts running in 2007, according to IBM.
IBM also announced that Cisco's IT department has acquired two SAN Volume Controllers.
"Customers' choices have been pretty limited until now," said Charles King, of Pund-IT Research in California. He noted that between IBM, EMC and Hitachi Data Systems, customers have more to choose from. But ultimately, he said, until all three companies' products are out in the market and available for side-by-side testing, questions will remain unanswered.