Big data refers to large, complex datasets that are difficult to process using traditional database management tools. There are four key characteristics of big data: volume, velocity, variety, and veracity. Various sources generate big data, including social media, scientific instruments, mobile devices, sensors, and more. Analyzing big data can provide benefits like cost reductions, time reductions, new product development, and smarter business decisions. Hadoop Distributed File System (HDFS) and Hadoop software are commonly used to store and analyze big data across clusters of commodity servers in a scalable, cost-effective manner.