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Larger SANs drive storage growth

Storage's exclusive Purchasing Intentions Survey polled 524 storage professionals. The survey suggests that storage managers are moving away from many small SANs to fewer, larger SANs that can power more services and connect to more places.

With shops growing by leaps and bounds, storage managers are moving away from many small SANs to fewer, larger SANs that power more services and connect to more places.

Storage managers are building larger, more centralized SANs, connecting to more diverse hosts and layering-in unprecedented levels of data protection. That's what the 524 storage professionals who responded to Storage's latest Purchasing Intentions Survey indicate.

How does your company's storage budget this year compare to last year?

Last spring, we reported that storage spending was growing, but that the rate of growth was down slightly (see "Storage spending report," Storage, June 2005). It has now headed back up again. Faced with the reality of ever-growing data volumes, storage managers are apparently getting the go-ahead to continue purchasing disk at brisk rates.

Our latest survey (see "About this survey") confirms a trend that emerged a year ago: More and more shops are building larger SANs and organizing them more around director-class switches than any alternative. By limiting the number of new fabrics and concentrating on adding services within the SAN, storage managers are able to move beyond just servicing high-performance, critical applications.

Data protection is chief among those services—disk-based backup, remote mirroring and tape archives—that reflect a push to improve disaster recovery (DR). Those technologies also help with ordinary business continuity and emerging compliance requirements.

Three years ago, 67% of respondents said their main reason for buying SAN switches was to "create a SAN." In the current survey, that figure dropped to 14% vs. 46% who said they were buying switches to expand their current SANs. In the intervening three years, as SANs have gone from pilot to production, storage managers have had several scalability options open to them; until recently, most simply built SAN islands that replicated DAS stovepipes.

Caught in inter-switch link (ISL) hell (where ISLs consume new ports), overwhelmed by data growth and underwhelmed by storage management tools, users have opted for an architectural approach to controlling storage network sprawl. When asked what their main switch architecture would be, a historically low 32% of those surveyed cited islands, which for the first time was surpassed by directors at 35% (see "Director switches are increasingly popular"). Other alternatives (notably Brocade Communications Systems Inc.'s core/edge topology) have shown little or no growth among survey respondents. And when users projected where they'd like to be by year's end, the trend was even more evident: 40% for directors, 26% for islands and 16% for core/edge.

Alongside this decisive shift toward large switches is a desire to consolidate. In March 2005, respondents indicated they would have fewer fabrics than in 2004; in this edition of the survey, they said they've stabilized at numbers similar to those from 2004, although they would still like to reduce that number. Consolidation may be running up against the relentless pace of storage growth, but it's still a goal.

Growing in tiers
Respondents indicate they're buying an average of 30TB of disk this year, which is 100% more than 24 months ago. With data volumes doubling every 12 to 24 months, this would suggest that growth is outpacing efforts to make more efficient use of storage.

Instead, storage managers are being selective as to which storage they buy. Their largest chunk of capacity buying overall is in the midrange (42%), with high-end storage now accounting for only 23% of purchases. Even in large companies (with more than $1 billion in annual revenue), midrange had a similar 41% of capacity, with high-end storage at 37% (see "Midsized storage is top choice of many shops," this page).

The use of different storage technologies at various but connected levels within the enterprise has taken root and is reflected in a number of significant trends:

  • Data protection has moved into a multitier mode, with disk moving increasingly into the short-term backup/restore function and tape assuming the longer term archive and comprehensive disaster recovery functions.

  • Networks are becoming multiprotocol, with iSCSI taking on backup and non-critical app traffic.

  • File storage increasingly involves the notion of a NAS head or other intelligent device, such as a shared file-system server, that addresses SAN storage.

The trend toward disk-based backup is undeniable, but users appear to be struggling with implementation. For the past two years, the majority of respondents indicated they were increasing their spending on disk-to-disk backup, but that percentage has crept up only slightly (from 51% to 55%) in that time. Perhaps more telling is that 25% of respondents haven't picked a disk-to-disk technology (see "Disk backup choices up in the air," below) and 24% haven't picked a primary vendor.

At the same time, storage managers have solidified their intent to use tape in the data protection process. While the number of people increasing their spending on tape had dipped below 40% in recent years, that number shot up to 48% this fall. In larger companies (more than $1B in revenue), 55% are increasing tape spending while 60% are increasing disk spending, suggesting that the "either/or" approach has been rejected (see "Tape and disk, not tape or disk"). Tape will be a part of the mix for 90% of those using disk-to-disk backup.

With DR spending strong (52% and increasing) and compliance requirements looming, storage managers are leveraging their tape infrastructures. Tape was tapped by 51% of those surveyed to meet compliance-related data retention requirements. While that was down from 54% a year ago, it still far outpaces disk-to-disk backup at 33%, with nothing else coming close to this figure (see "Tape leads for compliance").

But there's another change that shows users aren't simply reverting to past patterns: the growth of wide-area storage network links. A full 46% of respondents are increasing wide-area storage network expenditures, with another 25% maintaining spending levels. Those investing in wide-area technology are overwhelmingly being driven by their DR plan (60%). DR spending is increasing for 52% of respondents, while another 37% are maintaining DR spending levels.

Tape is a popular option for DR, with 42% of respondents citing it as their primary DR storage expenditure. But 45% cite remote copy or replication as their main DR approach. In a short period of time, storage managers have turned from tapes and trucks to data lines and disks as their DR front line of defense.

As they connect the dots between locations, storage managers are getting a host of other capabilities that come along for the ride: the ability to transmit data between centers for other purposes, notably automating remote site backup. Combined with the trend toward large, centralized fabrics, we're beginning to see the precursors to enterprise-wide SANs.


After punishing EMC Corp. for late technology, high prices and bad sales tactics in 2002, storage managers are increasingly turning to them as a primary vendor. EMC has widened its mindshare lead over the field in the latest Storage magazine Purchasing Intentions Survey in both disk and storage management software.

Traditionally, users have rewarded vendors that introduce new technology. Hitachi Data Systems' introduction of TagmaStore bought them a little bump, but IBM Corp.'s DS series seems to have had little effect. Still to be seen is whether Hewlett-Packard Co.'s recent signs of life will be reflected in greater mindshare among users.

In the switch market, the story is simple: Cisco Systems Inc. is riding the growing popularity of large switches into a leadership position in the market. The big loser: Brocade Communications Systems Inc., whose problems with product development in prior years, coupled with an inability to convince some shops that its director products are on a par with those of McData Corp. and Cisco, have led to steadily declining mindshare as a market leader.

Respondents to Storage magazine's Purchasing Intentions Survey have consistently cited product features and functions as their number one factor in choosing a primary vendor. That suggests that no vendor should get too comfortable on the throne.

ABOUT THIS SURVEY: Our survey was conducted in September 2005 by e-mail. Results are based on answers from 524 respondents, all of whom had specific purchasing authority for the product categories they were queried on.

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