Archive for September, 2009

Online vs Offline data storage

Sunday, September 20th, 2009

I have a ever rising need for data storage. Even if I stop accumulating data, or even cutting back what I store, I have to deal with failing media. I’ve had numerous hard drives die over the years, CDR’s have gone bad…

In my searches for cheap ways to store data, I came across some recommendations to use online storage. With Dreamhost offering 50GB for backups for free, this is something I’m going to start using. At $0.10 US/GB for overages, I hear it beats out quite a bit of competition. I’d prefer to stick with Dreamhost if possible as I know and use them.

Hard drive costs

So how much does hard drive storage cost, and how reliable is it? Well for the raw drive, I’ve recently been seeing about $1/GB CDN for SATA drives. My backup server is currently PATA with slow USB (likely version 1) so I’d likely need to spend some money upgrading the backup server. A cheap modern PC seems to go for about $300 CDN. I’d guess controller cards aren’t cheaper than $20.

Related costs

But the media cost isn’t the only cost. There’s also install time, maintenance time, and operation costs. One of the biggest operation costs at a house is electricity. Manitoba Hydro charges somewhere around $0.063/kwh CDN. That’s about 365.242199 * 24 * 0.063 = $552.246205 per kw-year.

Western Digital seems to say hard drives consume between 0.40 Watts to 5.4+5=10.4 Watts. I’ve seen elsewhere claiming 25 Watts for hard drives. So at the given kw-year, the cost of operation could be as low as about 0.40 * 552.246205 = $220 CDN. The more likely case of lets say 2 hours of operation, 1 hour idle to off, based on Western Digital’s “competing” write case of 5.4+4.5 watts in operation, 2.8 watts for idle, and 0.40 watts for standby is about
((((5.4 + 4.5) / 24) * 2) + (((2.8) / 24) * 1) + ((0.40 / 24) * 21)) * 552.246205 = $715.

Wow. I need to turn my computer off more often.

Simple comparisions

So lets take the best case for hard drives then and make it as big as seems reasonable right now. 1.5 TB is about 1,396.98386 GB. At Dream host, 3 years (typical hard drive warrenty) times 12 months times $0.10 times 1396 GB times 1.13 for padding for exchange rate, and possible volitility is about
3 * 12 * 0.10 * 1 396 * 1.13 = $5,679. Local storage would be $750 for electricty * 3 years, plus $150 for the hard drive, plus maintanence of lets say $250 is about (750 * 3) + 150 + 250 = $2,650.

So local storage is about half the cost in its best case. I’d say it’s more likely to be far less used, but at home I’d have to budget for expansion immediatly. Being at Dreamhost is good for a site disaster (like a house fire), but bad for access time.


More research is needed. If I had to make the decision tomorrow, I’d probably go with spending more on Dreamhost storage. I like the offsite feature, the low maintenance, and not having to spend as much time figuring out how much storage I might need.

Drew Scott Daniels’ resume