The increasing volumes of heterogeneous unstructured IoT data have also led to the emergence of several solutions to store these overwhelming datasets and support appropriate data management.

• NoSQL databases are often used for storing IoT big data. It is a new type of database which is becoming more and more popular among web companies today. Proponents of NoSQL solutions state that they provide more straightforward scalability and improved performance relative to traditional relational databases. These products excel at storing “unstructured data,” and the category includes open source products such as Cassandra, MongoDB, and Redis.
• In-memory databases assume that data is stored in computer memory to make access to it faster. Representative examples are Redis and Memcached, both NoSQL databases, entirely served from memory. These products excel at storing “unstructured data,” and the category includes open source products such as Cassandra, MongoDB, and Redis.