March 30, 2005, 4:43 PM — Technology managers seeking to reap the benefits of storage virtualization are at a crossroads, and two storage industry powerhouses, IBM Corp. and EMC Corp., 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 Corp. delivers on its alternative approach and both can be tested, the debate won't be settled.
Virtualization, 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 in Hopkinton, Massachusetts. 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 virtualization strategy that spans computing and storage, the benefit of its long history offering storage virtualization 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 Inc. 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.