# Redis

 In standalone installations the application uses a file-based storage for cache and session data. It allows the application to be used out of the box without any additional configuration. However, as application usage grows IO access can become a bottleneck. Redis is a great alternative which offers an open source, fast, in-memory, data store.

## Installation

  **Docker deployments**  
 No changes necessary! Redis is pre-installed and configured in our Docker deployments. 

 For information on how to download and install Redis, please visit <https://redis.io/download>.

## Configuration

For details on how to set the below configuration items, please read [Environment Variables](Updating+Config+Files#EnvironmentVariables).

  **[disable\_functions](https://www.php.net/manual/en/ini.core.php#ini.disable-functions) should not be configured**  
 To check whether `disable_functions` has values configured, open **Utilities -> System -> PHP Information** within the operator panel and search for `disable_functions`. `No value` will be shown if nothing is configured. Please also check the cron configuration, see [php command line options](https://www.php.net/manual/en/features.commandline.options.php) for guidance. 

To configure Redis the following environment variables should be used:

- `REDIS_HOST` - The IP address or hostname of the Redis server.
- `REDIS_PORT` - The port that Redis is running on. This environment variable is **optional** and defaults to `6379`.
- `REDIS_USERNAME` - The username to authenticate with, see [Redis security recommendations](https://redis.io/docs/management/security/#authentication).
- `REDIS_PASSWORD` - The password associated with the username, see [Redis security recommendations](https://redis.io/docs/management/security/#authentication). Redis versions prior to version 6 do not need to specify a username.

 Once authentication data has been configured, you can switch away from file-based storage drivers by specifying the following environment variables:

```

    CACHE_DRIVER=redis
    SESSION_DRIVER=redis

```