Big data refers to a collection of data that cannot be captured, managed and processed by conventional software tools within a certain time range. It is a massive, high-growth and diversified information asset, which needs a new processing mode to have stronger decision-making, insight and discovery, and process optimization ability. 5V characteristics of big data (proposed by IBM): volume (mass), speed (high speed), diversity (diversity), value (low value density) and authenticity, based on hadoop.