How to Install Memcached on Ubuntu 15.04

Memcached is a distributed, high-performance, in-memory caching system that is primarily used to speed up sites that make heavy use of databases. It can however be used to store objects of any kind. Nearly every popular CMS has a plugin or module to take advantage of memcached, and many programming languages have a memcached library, including PHP, Perl, Ruby, and Python. Memcached runs in memory and is thus quite speedy, since it does not need to write data to disk.

Pre-Flight Check

• These instructions are intended specifically for installing Memcached on a single Ubuntu 15.04 node.
• I’ll be working from a Liquid Web Core Managed Ubuntu 15.04 server, and I’ll be logged in as root.

Step #1: Install Memcached

As a matter of best practice we’ll update our packages:

apt-get update

Then installing Memcached and related packages is now as simple as running just one command::

apt-get install memcached

Step #2: Configuration of the Memcached Installation

Use the following command to view information on the memcached command:

memcached -h

The default configuration file can be found at:

/etc/memcached.conf

When started, Memcached will start on port 11211 by default per the default configuration file:

# Default connection port is 11211
-p 11211

To change the port, simply change the number in the configuration file.

For a refresher on editing files with vim see: New User Tutorial: Overview of the Vim Text Editor

EXAMPLE: If I wanted to run Memcached on port 1337, with 4GB of memory, and allow a maximum of 2,000 connections, I would change the config file as follows.

Let’s edit the configuration file:

vim /etc/memcached.conf

To the following:

-p 1337
-m 4096
-c 2000

Exit and save the configuration file, and then restart Memcached

service memcached restart