Database

Cardinal Home Server supports both SQLite and PostgreSQL. Each comes with their own advantages and disadvantages.

SQLite

SQLite is better choice for small to medium sized Home Server's.

SQLite is much faster than PostgreSQL, and using it will result in noticeably faster indexing and job times. In addition to performance, SQLite is more portable, making backups easy, and is lightweight so it's also good for low-powered hardware.

PostgreSQL

PostgreSQL is the better choice for high volume Home Server's.

PostgreSQL requires more hardware resources and is slower than SQLite, but it is much better at handling the concurrent writes of a highly active Home Server. It will also allow you to run multiple Home Server instances with the same database, something that SQLite can't do without interruptions.

I'm still not sure

Use SQLite.