By default there are always at least 2 redis server instances available:
- redis
- port 6379 (default)
- socket file: /var/run/redis/redis.sock
- Suitable for cache
- Volatile data/information
- Can be cleared at all times, shouldn't influence application when cleared
- Data = non persistent (volatile)
- redis-persistent
- port 6378 (non default)
- socket file: /var/run/redis-persistent/redis.sock
- Suitable for sessions
- Persistent data/information
- Should/will never be cleared, clearing would influence application
- Data = persistent (non-volatile)
Notes:
- Using the socket file is recommended when using local redis instances (less overhead = better performance!)
- Try to use seperate databases when having multiple websites/applications on the same server (e.g. db 1 , db 2, ...)
- By default there are 16 databases available (0-15), this could be increased on request
- Sample Magento 2 env.php with redis configured properly can be downloaded HERE (Magento < 2.3.5) and for Magento 2.3.5 and newer HERE