As past surveys have shown, the need for more disk capacity is the leading reason why storage managers make new storage technology purchases. Last spring, respondents planned to add an average of 37TB of storage capacity; in the most recent survey, that number edged up to 40TB--33% higher than one year ago. That's not a total of 40TB of installed storage, it's 40 new terabytes of capacity: additional disks in existing arrays and entirely new disk subsystems (see "Planned disk storage purchases ," at right). Given the level of growth, it's not surprising survey respondents indicated that 59% of their disk expenditures in 2006 will be for new SAN arrays (see "Primary disk storage expenditures ," below).
The Chicago Mercantile Exchange's (CME) storage budget rose approximately 10% this year, with much of that increase earmarked for new storage systems. But increasing capacity isn't the firm's only issue. "It's less about capacity," says Joel Kulesa, storage architect at the CME, "but more about transaction rates and number of physical volumes, which have been increasingly fast."
Adding disk to achieve better performance doesn't necessarily mean upping the number of spindles in existing arrays. "We get better transaction rates by adding more storage frames and fewer single points of failure," says Kulesa. He also sees some economy in adding entire frames, rather than increasing the number of disks in the firm's existing tier-one EMC Corp. and Hitachi Data Systems (HDS) Corp. arrays. "Adding drives costs almost as much as adding another storage frame," he notes. Kulesa says the CME has looked into alternatives to high-end arrays, but the prospects haven't been compelling as yet. "We've been a little hesitant to jump on those platforms for our high-availability projects," he says. "Their costs aren't dramatically low enough to make it worthwhile to try."
For some companies, disk represents a major portion of their storage budget because they've undertaken major storage restructuring projects. Stewart Taylor, manager of information technology at Creative Benefits, a Vista, CA-based benefits outsourcing firm, reports that his storage budget rose approximately 10%, with the increase almost entirely earmarked for revamping the storage infrastructure. Taylor replaced a mostly DAS environment with a Compellent Technologies Storage Center array. "This was a major deal," he says, and not necessarily representative of typical budgeting at the company. He says dramatic price decreases for storage arrays made the transition feasible. "When I first got onboard, they told me to look into it [a SAN] and it was over $300,000," says Taylor. "Now we're down to $70,000." Creative Benefits also evaluated other vendors' arrays, with Compellent and Network Appliance (NetApp) Inc. emerging as its two finalists. In the end, functionality and price were the decisive factors. "The NetApp had a lot of whistles and stuff," says Taylor, "but, boy, each one of them costs."
The storage budget for the City of North Vancouver, British Columbia, also increased. While much of this year's budget growth was to accommodate salary increases, a portion of the budget was designated for a DAS-to-networked storage migration, among other projects. "We're pretty much redoing our operational infrastructure," says Craig Hunter, manager of IT for the city. The keystone of North Vancouver's upgrade project was the addition of a NetApp array with 3TB of capacity. Hunter is well along with preparations for his 2007 budget, which he expects to be similar to this year's. "At this point, it's probably in that range for next year," says Hunter, who hopes to add another array. "Longer term--six months, I guess--we'll have a DR [disaster recovery] SAN at our business-continuity site."
The storage purchases made by Kulesa, Taylor and Hunter reflect the disk subsystem purchasing patterns of the aggregate survey responses. Larger companies overwhelmingly opt for high-end disk systems, such as the EMC Symmetrix and HDS TagmaStore USP that Kulesa says are staples of his shop. Predictably, midsized businesses are more likely to purchase midrange systems, such as the Compellent and NetApp boxes acquired by Taylor and Hunter.