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Tape vs. Disk: Tape Refuses to be Evicted

By Drew Robb (Send Email)
Posted Nov 16, 2009


For the past five years or more, articles have been appearing about the death of tape. virtual tape libraries (VTLs) and other disk-based backup strategies have been held up as more efficient, faster and so on. The rise of deduplication seemed to reinforce this message by making it possible to pack around 20 times more backup data onto disk.

Like a tenant who refuses to be evicted from an area earmarked for redevelopment, tape is alive and kicking. When it comes to long-term backup retention and archiving, it is holding its own against dedupe — especially among large enterprises.

Certainly, tape has lost a lot of ground to disk, particularly at the lower end of the market, and as a repository for recent backup data. Like a tenacious tenant who refuses to be evicted from an area earmarked for redevelopment, tape is alive and kicking. And for long-term backup retention and archiving, tape appears to be holding its own — especially among large enterprises.

This was brought home recently vendors Quantum and Spectra Logic approached ServerWatch for pre-briefs on their latest tape offerings. PR agencies and vendors expending effort to develop, manufacture and market brand new tape libraries? They wouldn't be doing it if they couldn't turn a profit with these products. And they can.

How are tape sales? IDC references several studies. Tape overall is down, although the slide is mainly at the lower end. Robert Amatruda, a tape analyst for IDC, said that the market for tape automation products below 100 tape cartridges would suffer most. Another IDC study on Asia-Pacific sales from last year showed automated tape libraries to be up 15 percent for the year, while tape drives fell 19 percent. Cheryl Ganesan-Lim, an IDC analyst, noted that disk storage allows better recovery speeds, thus making it suitable for Tier 1 and Tier 2 storage. Tape, on the other hand, is better for deep archiving of rarely accessed data. She expected tape library sales to rise slightly over the next five years.

So tape is down in lower-end, smaller-scale and more immediate data recovery categories, but it is largely holding its own at the high end. It looks like tape's death isn't imminent.

Why Tape Hangs On

So why hasn't tape quietly faded away? Molly Rector, vice president of marketing and product management at Spectra Logic, stated the one fact that disk vendors just can't defend. Tape is much less expensive. She agreed with the IDC view that tape's role is to function as part of a tiered infrastructure in which it is used for archiving.

"We are seeing growth in sales in our tape products," said Rector.

Accordingly, the company just rolled out its latest and greatest. The Spectra Logic T-Finity enterprise tape library comes with multiple, redundant robots and can scale to 45 petabytes (180 PB by combining four boxes into a unified library complex). Rector boasts that this offers the highest storage density available today — 72 TB per square foot — and it scales to more than 30,000 slots in one library. In terms of power efficiency, she reckons it destroys the competition. One slide indicated the T-Finity toasts the IBM TS3500 and the Sun STK SL8500 on watts per TB and overall heat dissipation.

"The T-Finity uses a third to half of the power of its closest competitors, per unit of data stored," said Rector.

The T-Finity comes with all of the enterprise bells and whistles you would expect with regard to management (e.g., encryption and key management — the press release gives full details). It begins shipping in December, and pricing starts a little above $200,000.

As an indicator of growing respect for Spectra Logic among the enterprise-class, Rector said the company already provides the tape libraries for 7 of the 10 top supercomputing sites in world. As such, the company is focusing on the Federal government, broadcast/media/entertainment and supercomputing/HPC markets. Beta customers for the T-Finity include NASA Ames and Argon National Labs.

She reported that 70 percent of customers are encrypting data, as it is now easy to do so. What if the CEO makes some request to find a word document he deleted a year ago? According to Rector, it would take two minutes to find a specific file. In addition, the system verifies data was actually written correctly, thereby avoiding the embarrassment of finding an old tape is blank.

Needless to say, Rector has confidence in the future of tape.

"While the low end is shrinking, the mid and upper ranges of the market are either flat or growing a little — and tape still represents a $3.6 billion sector," said Rector.

She admitted that disk makes more sense in the small office/branch office setting. But she also pointed out that many of the companies that use disk for that purpose back up from disk to a large tape library once the data is centralized.

What about all those stories of tapes breaking and the general unreliability of tape? Rector agreed that older systems had plenty of problems in this regard. But she accused disk vendors of painting unfair comparisons between old tape systems and brand new disk set ups.

"Older tape systems had problems, but today's libraries don't," said Rector. "Tape is as reliable as disk if you go with latest systems."

Drew Robb is a freelance writer specializing in technology and engineering. Currently living in California, he was originally from Scotland where he received a degree in Geology/Geography from the University of Strathcyle. He is the author of Server Disk Management in a Windows Environment (CRC Press).

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