Published: 09 Dec 2005
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.
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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.
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.
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.
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.
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.