From a post by Derrick Harris at GigaOm:
A fully sequenced human genome results in about 100GB of raw data, although DNAnexus Founder and CEO Andreas Sundquist told me that volume increases to about 1TB by the time the genome has been analyzed. He also says we’re on pace to have 1 million genomes sequenced within the next two years. If that holds true, there will be approximately 1 million terabytes (or 1,000 petabytes, or 1 exabyte) of genome data floating around by 2014.
Why, that’s more than the number of books in the Library of Congress times miles to the moon plus the length of all football fields laid end to end!