A yottabyte is a data storage benchmark that's equal to 1,000 zettabytes. The total amount of data stored worldwide is expected to reach 2.7 zettabytes this year, up 48 percent from 2011, according to an IDC calculation. So we're a long way from reaching the yottabyte threshold -- although with the rate of big data growth, it might come sooner than we think.
Just to review, a zettabyte is one sextillion bytes of data. It's equal to 1,000 exabytes, 1 million petabytes and 1 billion terabytes.