Install and configure Redis with Nextcloud on Debian

Redis is an open-source, ultra-fast in-memory key-value database. In the context of Nextcloud, Redis is primarily used to enhance performance by managing user sessions, file locks, and caching. In this comprehensive guide, we will explain how to install Redis, configure it, and integrate it with Nextcloud on a Debian server.

Prerequisites​

• Debian 10 or higher server
• Nextcloud already installed
• Access to a terminal with sudo privileges or root user

Step 1: Install Redis on Debian

System update

Before installing Redis, it is advisable to update your system to obtain the latest versions of the available packages.

sudo apt update
sudo apt upgrade -y

Redis Installation

Redis is available in the official Debian repositories. To install it, run the following command:

sudo apt install redis-server -y

Installation verification

Once the installation is complete, you can verify that Redis is working correctly by running the following command:

redis-server --version

And to check if the Redis service is running:

sudo systemctl status redis-server

If Redis is running, you should see a message indicating that the service is active.

Step 2: Install PHP-Redis for Nextcloud

Nextcloud requires the PHP extension for Redis. You need to install this extension for Nextcloud to interact with Redis. Run the following command to install php-redis:

sudo apt install php-redis -y

Once the extension is installed, restart your web server to apply the changes:

sudo systemctl restart apache2   # For Apache

Or for Nginx:​

sudo systemctl restart nginx

Step 3: Configure Redis for Nextcloud

Edit the Nextcloud configuration file

Nextcloud must be configured to use Redis as a cache, to manage user sessions, and for file locking. The Nextcloud configuration file is usually located in the /var/www/nextcloud/config/config.php directory. Open it with a text editor:

sudo nano /var/www/nextcloud/config/config.php

Add the following lines to this file to configure Redis as a caching and session management system:

<?php
$CONFIG = array (
  // Using Redis for local caching
  'memcache.local' => '\OC\Memcache\Redis',
  'redis' => array(
      'host' => 'localhost',
      'port' => 6379,
      'timeout' => 0.0,
  ),
  // Using Redis for session management
  'session_save_path' => 'tcp://localhost:6379',
  // Using Redis for file locks
  'filelocking.enabled' => true,
  'locking.cache' => 'redis',
);

Explanation of options

• memcache.local : Redis is used as a local cache to improve performance.
• redis : Configure the connection settings for Redis (here, localhost and the default port 6379).
• session_save_path : Use Redis to store user sessions.
• filelocking.enabled : Enables the use of Redis to manage file locks.

Once you have added these lines, save and exit the file (Ctrl + O to save, then Ctrl + X to exit).

Step 4: Restart Nextcloud

After configuring Redis in Nextcloud, you need to restart your web server to apply the changes:

sudo systemctl restart apache2   # For Apache

Or for Nginx:​

sudo systemctl restart nginx

Step 5: Configuration Verification

Check the operation of Redis with Nextcloud

You can test that Redis is properly configured by connecting to the Nextcloud web interface and observing if the performance has improved. Additionally, you can check the Nextcloud logs for any errors related to Redis by running:

sudo tail -f /var/www/nextcloud/data/nextcloud.log

Check that Redis is working

Make sure that Redis is working properly by checking its status:

sudo systemctl status redis-server

If Redis is properly configured and everything is working, you should see a message indicating that Redis is active.

Step 6: Optimizing the Redis Configuration

Configure data persistence

Redis can be configured to use two persistence mechanisms: RDB (Snapshots) and AOF (Append Only File). If you want to ensure that your data is not lost in the event of a server restart, you can enable either of these mechanisms.

1. Configure RDB persistence : This allows Redis to create snapshots of the database at regular intervals. This option is enabled by default, but you can adjust the settings in the configuration file /etc/redis/redis.conf.
   Example of RDB configuration (default values):

   
   save 900 1
   save 300 10
   save 60 10000
   

2. Enable AOF persistence : To enable the AOF option, search for and modify the following line in /etc/redis/redis.conf :

   appendonly yes
   

3. Limit memory usage : Redis can be configured to use a maximum amount of memory. For example, to limit Redis to 256 MB of RAM, you can add the following line in /etc/redis/redis.conf :

   maxmemory 256mb
   maxmemory-policy allkeys-lru
   

   This sets a memory limit and applies the LRU (Least Recently Used) policy to evict the least used keys when the memory is full.

Enable logging in Redis

You can also enable logging to track Redis errors. To do this, modify the following line in the /etc/redis/redis.conf file:

logfile /var/log/redis/redis-server.log

Don't forget to restart Redis after making these changes:

sudo systemctl restart redis-server

Step 7: Securing Redis

It is strongly recommended to secure Redis, especially if you expose it to the Internet. Here are some best practices:

1. Enable a password for Redis : You can configure a password for Redis in the configuration file /etc/redis/redis.conf. Look for the following line and uncomment it :

   
   requirepass your_password
   

2. Limit access to Redis : Make sure that Redis is only accessible from your Nextcloud server by configuring the firewall. If you are using ufw, allow only local connections to Redis. :

   sudo ufw allow from 127.0.0.1 to any port 6379
   

3. Disable dangerous commands : You can also disable certain potentially dangerous commands (such as FLUSHDB or FLUSHALL) in the file /etc/redis/redis.conf to enhance security.

Conclusion

You have now configured Redis with Nextcloud on your Debian server, which improves performance by reducing response times through session management, file locking, and caching. Redis is a powerful solution for optimizing the use of Nextcloud, especially if you are managing an installation with many users and files.

En suivant ce guide, vous avez installé et configuré Redis, adapté la configuration à vos besoins, et sécurisé votre installation. Vous pouvez maintenant profiter de meilleures performances et d’une expérience utilisateur plus fluide avec Nextcloud.