Apache Hadoop is an open source software framework for storing and processing large volumes of distributed data. It provides a set of instructions that organizes and processes data on many servers rather than from a centralized management nexus.
Apache Hadoop data systems are not limited in their scale. More hardware and clusters can be added to handle more load without reconfiguration and purchasing expensive software licenses.
For decades, organizations relied primarily on relational databases (RDBMS) in order to store and query their data. But relational databases are limited in the types of data they can store and can only scale so far before you must add more RDBMS licenses and dedicated hardware. Thus, there was no easy or cost-efficient way for companies to use the information stored in the vast majority of non-relational data, often referred to as "unstructured" data.
Thanks to greater digitization of business processes and an influx of new devices and machines that generate raw data, the volume of business data has grown precipitously, ushering in the era of "big data". Subsequently, this inability to use other sources of data became an increasing source of unrest. The Apache Hadoop project provided a viable solution by making it possible and cost-effective to store and process an unlimited volume of data.&
As an open source project, Apache Hadoop is not a product but instead provides the instructions for storing and processing distributed data; a variety of software manufacturers have used Apache Hadoop to create commercial products for managing big data.