Redis

Redis is a key-value storage system. Similar to Memcached, it supports stored value types are relatively more, including string ( string ), list ( list), set ( set ) and Zset ( set ). These data types are supported by push / pop, add / remove and intersection and set difference set and more rich and the operation, and the operation is atomic. On the basis of this, redis supports a variety of different ways to sort. As with the memcached, in order to ensure efficiency, data is cached in memory. The difference is the redis would periodically to update data to disk or to modify operation to write additional log files, and on this basis to achieve the master-slave ( slave ) synchronization.