“Big data” is coined to address massive volumes of data sets usually huge, sparse, incomplete, uncertain, complex or dynamic, which are mainly coming from multiple and autonomous sources. The primary sources for big data are from business applications, public web, social media, and sensor data and so on. “Big data mining” involves knowledge discovery from these large data sets. “Big data” is gaining huge significance in the current scenario and consequently, big data mining emerged as an innovative and potential research area. This paper gives an overview of big data along with its type, source and characteristics. A review on various big data mining platforms, algorithms and challenges is also discussed in this paper.