Install and Use Redis

Redis is an open source, BSD licensed, advanced key-value store. Redis holds its database entirely in memory, using the disk only for persistence. Redis can replicate data to any number of slaves.

Installing Redis

• Download the latest stable release tarball or wget http://download.redis.io/releases/redis-stable.tar.gz

• Untar it:

           tar xzf redis-stable.tar.gz

• Change Directory or make entry to '.bashrc':

          cd redis-stable

• Proceed to with the make command:

          make

• Run the recommended make test:

          make test

• Start Redis

hduser@slave:~$ redis-server
8413:C 02 Feb 13:29:24.587 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
8413:M 02 Feb 13:29:24.591 # You requested maxclients of 10000 requiring at least 10032 max file descriptors.
8413:M 02 Feb 13:29:24.592 # Redis can't set maximum open files to 10032 because of OS error: Operation not permitted.
8413:M 02 Feb 13:29:24.594 # Current maximum open files is 4096. maxclients has been reduced to 4064 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'.
8413:M 02 Feb 13:29:24.595 # Warning: 32 bit instance detected but no memory limit set. Setting 3 GB maxmemory limit with 'noeviction' policy now.
                _._
           _.-``__ ''-._
      _.-``    `.  `_.  ''-._           Redis 3.0.7 (00000000/0) 32 bit
  .-`` .-```.  ```\/    _.,_ ''-._
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
 |    `-._   `._    /     _.-'    |     PID: 8413
  `-._    `-._  `-./  _.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |           http://redis.io
  `-._    `-._`-.__.-'_.-'    _.-'
 |`-._`-._    `-.__.-'    _.-'_.-'|
 |    `-._`-._        _.-'_.-'    |
  `-._    `-._`-.__.-'_.-'    _.-'
      `-._    `-.__.-'    _.-'
          `-._        _.-'
              `-.__.-'

8413:M 02 Feb 13:29:24.599 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
8413:M 02 Feb 13:29:24.601 # Server started, Redis version 3.0.7
8413:M 02 Feb 13:29:24.601 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.
8413:M 02 Feb 13:29:24.601 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
8413:M 02 Feb 13:29:24.602 * The server is now ready to accept connections on port 6379

• Check if redis is working?

hduser@slave:~$ redis-cli
127.0.0.1:6379> ping
PONG
127.0.0.1:6379>

This shows that you have successfully installed redis on your machine.

To get all configuration settings
127.0.0.1:6379> CONFIG GET *
  1) "dbfilename"
  2) "dump.rdb"
  3) "requirepass"
  4) ""
  5) "masterauth"
  6) ""
  7) "unixsocket"
  8) ""
  9) "log
  ...
  ...