Big data refers to extremely large data sets that are difficult to process using traditional data processing tools. It is characterized by volume, velocity, variety, veracity and variability. Big data comes in both structured and unstructured formats from a variety of sources. To effectively analyze big data, platforms must be able to handle different data types, large volumes, streaming data, and provide analytics capabilities. The five key aspects of big data are volume, velocity, variety, veracity and variability.