The best to use depends on what you want to do with it. rrd4j doesn’t support Switches and Contacts anymore so that one is not a good choice. Mapdb only saves the most recent state and is an excellent choice for restoreOnStartup or if all you care about is the time of the most recent update to the Item.
Beyond that I can’t tell you what is the “best” because it depends on what you want to with the data and your level of experience.
