How To Install Memcached on Debian 9

In this tutorial, we will show you how to install Memcached on Debian 9. For those of you who didn’t know, Memcached is a system daemon that allows you to cache information on RAM memory, this allows you better app speeds and avoids bad performance on your dedicated or VPS server. It is very useful for optimizing dynamic websites and enabled speed by caching objects in memory.

This article assumes you have at least basic knowledge of Linux, know how to use the shell, and most importantly, you host your site on your own VPS. The installation is quite simple and assumes you are running in the root account, if not you may need to add ‘sudo‘ to the commands to get root privileges. I will show you the step-by-step installation of Memcached on a Debian 9 (Stretch) server.

Prerequisites

• A server running one of the following operating systems: Debian 9 (Stretch).
• It’s recommended that you use a fresh OS install to prevent any potential issues.
• SSH access to the server (or just open Terminal if you’re on a desktop).
• A non-root sudo user or access to the root user. We recommend acting as a non-root sudo user, however, as you can harm your system if you’re not careful when acting as the root.

Install Memcached on Debian 9 Stretch

Step 1. Before we install any software, it’s important to make sure your system is up to date by running the following apt-get commands in the terminal:

apt-get update
apt-get upgrade

Step 2.  Installing Memcached.

Now use the following command to install the Memcached service on your system:

apt-get install memcached netcat

Step 3. Configuration Memcached.

The default configuration file can be found at:

nano /etc/memcached.conf

Change the settings, Example settings for 512MB caching:

# Start with a cap of 64 megs of memory. It's reasonable, and the daemon default
# Note that the daemon will grow to this size, but does not start out holding this much
# memory
-m 512

# Default connection port is 11211
-p 11211

# Run the daemon as root. The start-memcached will default to running as root if no
# -u command is present in this config file
-u memcache

# Specify which IP address to listen on. The default is to listen on all IP addresses
# This parameter is one of the only security measures that memcached has, so make sure
# it's listening on a firewalled interface.
# -l 127.0.0.1

Exit and save the configuration file, and then restart Memcached:

systemctl restart memcached
systemctl enable memcached

Step 4. Configure Firewall for Memcached.

Run the following commands to allow the incoming connection on Port no 11211:

firewall-cmd --permanent --zone=public --add-port=11211/tcp
firewall-cmd --reload

Step 5. Installing Memcached extension for PHP.

You will also need to install the required PHP extension for Memcached:

apt-get install php-memcached

Now, we can restart Apache so that the changes take place:

systemctl restart apache2

To test PHP, create a test file named info.php with the content below. Save the file, then browse to it to see if PHP is working:

nano /var/www/html/info.php

<?php
phpinfo();
?>

Congratulations! You have successfully installed Memcached. Thanks for using this tutorial for installing Memcached on Debian 9 (Stretch) system. For additional help or useful information, we recommend you to check the official Memcached website.