Hadoop is an apache based open-source software framework for storing data and running applications on clusters of commodity hardware. Hadoop is written in Java. It provides massive storage for any kind of data, enormous processing power and the ability to handle virtually limitless concurrent tasks or jobs.
Big Data is a phrase used to mean a massive volume of both structured and unstructured data that is so large that it is difficult to process using traditional database and software techniques.
Big Data Hadoop is nothing but Hadoop- an open-source software which is developed to handle the big data- a huge amount of data.
Various techniques used by Hadoop are Hadoop Distributed File System (HDFS), HBase, HIVE, Sqoop, Hadoop PIG, Zookeeper, NoSQL, MapReduce, Oozie, Clouds, Spark, MongoDB, Apache Flume and many more.