Added in version 1.3.0.

The databaseTuning option controls how Syncthing uses the backend key-value database that stores the index data and other persistent data Syncthing needs. In most cases this database is fairly small (hundred megabytes or less) and the default tuning is optimized for this. However in cases with large folders or many devices the database may grow, and updates may be more frequent. In these cases it’s better to use larger buffers, allow more memory to be used for cache, allow a larger amount of overhead on disk in order to improve compaction performance, and so on.

The databaseTuning option can have one of three values:

  • small: This is the old set of tuning parameters, recommended for small databases.

  • large: This is a new set of tuning parameters, recommended for large databases.

  • auto: Syncthing will automatically use either the large or small tuning parameters depending on the database size on disk. A database that is 200 MiB or more in size is considered “large” for the purposes of this option.

The default value is auto.