Cassandra is a distributed data storage system for handling very large amounts of structured data. Generally these data are spread out to many commodity servers. Cassandra gives you maximal flexibility to distribute the data. You can also add storage capacity of your data keeping your service online and you can do this task easily. As all the nodes in a cluster are same, there is no complex configuration to deal with. Cassandra is written in Java. It supports mapreduce with Apache Hadoop. Cassandra Query Language (CQL) is a SQL-like language for querying Cassandra Database.
Redis is a key-value store. Furthermore, it is the most famous key-value store. Redis has support for some C++, PHP, Ruby, Python, Perl, Scala and so forth. Redis is composed in C language.
Furthermore, it is authorized under BSD.
HBase is a distributed and non-relational database which is designed after the BigTable database by Google. One of the main goals of HBase is to host Billions of rows X millions of columns. You can add servers anytime to increase capacity. And multiple master nodes will ensure high availability of your data. HBase is composed in Java. It’s authorized under Apache. Hbase accompanies simple to utilize Java API for customer access.