Applications such as CRM and ERP create huge amounts of data. Moreover, the data generated by these enterprise applications is likely to be in demand all over the company so that marketing, sales and service reps can respond to customer buying habits and sales trends.

Trouble is, many data caches reside on direct attached storage (DAS), which can’t share data?or capacity?between different servers, let alone across a company. Not only does DAS make it difficult to satisfy user demands, but IT executives are forced to buy more storage?and hire more people to administer the system?even though there is still unfilled capacity in their data center. "[That] costs a lot of money," says George Medairy, director of corporate IT at Sheetz, a $2 billion convenience store company based in Altoona, Pa. "We have hundreds of thousands of dollars invested in various aspects of storage."

Enter the storage network, which evolved in answer to the DAS problem. By pulling storage devices onto a network, companies can theoretically get rid of the interconnectivity problem and manage capacity better. Jerry McElhatton, president of global technology and operations at MasterCard International in Purchase, N.Y., has put together a centralized storage center with several storage area networks that run 130 terabytes of storage. He says that even though the company’s applications have grown hugely, "we’re able to add more storage without adding more people to maintain it. The cost per byte of storage is actually less than before we put this in."

McElhatton’s solution makes a lot of sense. But storage networks?be they storage area networks (SANs), network attached storage (NAS) or some derivation of Internet protocol storage?add wrinkles of their own to the challenge of managing storage. For example, a DAS scheme generally means dealing with one or two vendors. In contrast, Glasshouse’s Shirman says, the average SAN, which requires software and networking technology as well as the storage hardware, can use products from five to seven vendors.

As a result, IS departments need more software and services in order to manage the networks, allocate storage capacity and get various vendors’ products to work together. In fact, some analysts are saying that the budget that used to go to hardware is merely moving over to accommodate the increased need for services and software. Storage hardware vendors such as EMC are reading the tea leaves the same way and branching out into software and services in an effort to retain market share.