Database backends
Minetest supports several database backends. This page provides a comparison of all 3 (actually 4, but the dummy backend generally isn't useful) backends.
The database backend is set using the backend setting in world.mt.
If you want to migrate a world to a new backend, use minetestserver --migrate <name of new backend> --world <path to your world directory>.
Comparison table
| Backend | Speed | Reliability | Compatibility with builds |
|---|---|---|---|
| SQLite3 |
Acceptable |
Acceptable (db can corrupt if accessed while open) |
Very good (supported by any Minetest version) |
| LevelDB |
Good |
Good |
Mostly supported |
| Redis |
Very good (most data is always kept in RAM) |
Good |
Bad (needs a running Redis server) |
| Dummy |
Very good (all data is always kept in RAM) |
N/A (nothing is saved to disk) |
N/A (nothing is saved to disk) |
The Compatibility with builds column is only relevant if you want to distribute the worlds.
SQLite3
SQLite3 is the default backend for all Minetest worlds, it is supported by every Minetest build and is therefore the standard database format that is used to distribute worlds.
LevelDB
LevelDB is mostly used on servers because of its improved reliability and the ability to use more than 4 GB of space. You need to install it additionally.
Redis
Redis support was added to Minetest in April 2014, redis is mainly useful for servers as it allows multiple worlds to be stored in one redis instance. You need to install it additionally (libhiredis library).
Information about setting up a redis server can be found here: http://redis.io/topics/quickstart
world.mt settings for Redis
redis_address -- The IP or hostname of the redis server.
redis_port -- The port of the redis server. Optional, default: 6379
redis_hash -- Hash where the MapBlocks are stored in, if you want multiple worlds in one redis instance this needs to be different for each world. If you don't need any hash, you can write IGNORED.
Dummy
A dummy database backend, which stores all MapBlocks in RAM without saving them and will most likely not be of any use for you.