I'm clearing out some of the blog posts I've clipped over the years and came across one that I saved when I was working on DPM. Jonathan Schwartz's article on how long it takes to move a petabyte of data caught my attention because it related to the DPM issue of when you might prefer tape storage to disk storage.

A petabyte is awfully huge, of course. As he explains, "A petabyte is a thousand terabytes, which is a million gigabytes, or a billion megabytes. Or 8 billion megabits." But thinking it over...my own little PC at home has 500 GB now. And 2000 workstations could be a decent size company. Not that all those workstations would fill up their 500 GB hard drives, but it made the data size not so inconceivable to me. Lots of servers, lots of data to maintain and archive - the numbers could get pretty big.

Then he does the math:

"So if you had a half megabit per second internet connection, which is relatively high in the US (relatively low compared to residential bandwidth available in, say, Korea), it'd take you 16 billion seconds, or 266 million minutes, or 507 years to transmit the data."

Thus supporting his contention that it is "faster to send a petabyte of data from San Francisco to Hong Kong by sailboat, than by the internet." Cool, huh?