Monday, July 19, 2010

The bandwidth of a fully laden 747

Never underestimate the speed of shipping physical stuff when you want to move large amounts of data. The Internet is actually horribly slow even at 'high' speeds. That's why Amazon Web Services offers an Import/Export service that involves shipping physical disks around.

Back in 1999 I wrote an article for The Guardian explaining latency and bandwidth for modem users. In it I used a jet plane full of people flying across the Atlantic to illustrate the difference.

The analogy still works today, and brings me to the farcical question: what's the bandwidth of a fully laden 747?

Assuming I fill it with DAT 320 cartridges, each of which can contain 160GB of uncompressed data and each of which weigh about 50g then I can fit about 2.8m cartridges in the plane (a single 747 can lift 140 tonnes). That's about 427 PB of storage in the plane. (I'm not sure that many cartridges will actually fit inside the 747, but you get the idea).

Now assume it flies from San Francisco to London in 10 hours. That's a bandwidth of about 12 TB/s.

Which brings me to today's announcement from RackSpace about OpenStack. One of the goals of OpenStack is to remove lock in to specific providers. That's a noble goal, but if you store a lot of data in the cloud you might find yourself needing a 747 (or at least FedEx) if you decide to change providers.

PS Many people have commented that it would take a while to fill up the DAT tapes. Clearly the solution, as one commenter suggests, is to use a 747 as your data centre and fly it where you need.


If you enjoyed this blog post, you might enjoy my travel book for people interested in science and technology: The Geek Atlas. Signed copies of The Geek Atlas are available.


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