No Question About it: Sometimes Tape is the Answer

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Dear Ms. Meade:
My data crunching company generates 2-3 TB of data per customer, and I need to store that somehow. However, I don’t have room for a tape library. The only thing I can think to do is put the data on some hard drives using Linux-based RAID software, then put the disk in a safety deposit box. Do you have any other suggestions?”
Short on Space

Dear Ms. Space:
You have money and room for terabytes of disk storage, which you will squirrel away in a pretty large safety deposit box, but not a couple of dollars and rack units for a small library? Hmmm.

In pondering a polite answer to this question, Ms. Meade called to mind something similar posted on Slashdot, and is heartened that several intelligent points were discussed in that context. Being one to always encourage others in the path of light, Ms. Meade will summarize these intelligent comments and add to them.

The Short Version, by the way, in case you are averse to reading: Buy an LTO-4 tape drive and LTO-4 tapes. Forget the disk.

The Long Version: As fond as Ms. Meade is of disk, especially Spectra nTier disk, Ms. Meade understands that disk’s greatest asset is the speed at which it retrieves data—NOT its use for secure offline data storage.

Tape is cheaper than disk, even the disk to which you are likely referring. The Tape Equation: you can buy an LTO-4 tape drive for around $1400 (and likely for less), and at $40 per tape, store 800 GB of data; with these and a little compression, you are two tapes away from serious, long-term storage.  Assuming that you have more than a handful of customers annually, this pays for itself pretty rapidly, compared to purchasing cheap (and risky) jbod.

At $100/TB per hard drive and twenty customers each with 2 TB of compressed data, annually the company must shell out $4,000 per year. If, instead, the firm purchases a tape drive and LTO media, your costs are under that in just the first year– about $2,000 for tape, and another $1,400 for the drive. You’ve paid for the drive in one year. After that, you save $60/TB. (That translates to thousands of dollars annually.)

You may want to consider a tape library, which truly are not space- or budget-hogs. Libraries such as the 4U Spectra T50e may be worth the space and time simply in convenience. This depends a great deal on your business volumes and staffing, and Ms. Meade acknowledges constraints due to current recessionary times. However, to emphasize the point: a relatively lightweight investment such as the purchase of a small library can automate data protection—and most companies that deal in data understand that their business also mandates data-caretaking.

For those unenlightened few who say that LTO tape is not a wise choice because eventually new technologies replace older ones, please consider that LTO has been around this past decade and shows no sign of going away. No migration will be necessary for years to come, given that current generations of LTO tape technology read data on tape that is two generations back, and write one generation back. With new generations about every 3 years, and giving the mobility of today’s clientele, the lifespan of at least 6-10 years is likely sufficient for your business requirements.

Frankly, the issue truly cries out for tape, and Ms. Meade is glad to add her voice to those doing the crying out.