Redis is the most popular key-value, open source and in-memory data structure store that can be used as a database. Here in-memory means that instead of storing the data on disk redis relies on main memory for data storage. As a result redis databases are faster than other relational databases because memory access is faster than the disk access.While querying the data from in-memory database takes less time which provides faster and better performance.

So the applications where response time is critical we should use in-memory database.It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets and sorted sets. Data from one Redis server can be replicated to any number of servers called as slaves. This allows Redis to implement a single-rooted replication tree. Apart from all these what makes redis more incredible is persistence of data to disk, which means redis can be used as a real database instead of a voletile cache and unlike memcached data would not disappear whenever we restart.

Lets install redis on ubuntu:

First updating all of the apt-get packages:

sudo apt-get update

Download a compiler with build essential:

sudo apt-get install build-essential

Then download tcl:

sudo apt-get install tcl8.5

Download the required redis version from Redis.io.

wget http://download.redis.io/releases/redis- 3.07.tar.gz

Untar it and switch into that directory:

tar xzf redis-3.07.tar.gz

cd redis-3.07

Run make command:

make

Run the recommended make test:

make test

Finish up by running make install:

sudo make install

To run the server:

redis-server