The world data, which also includes player inventories, is saved to a folder in the current working directory of the server.

The name of the folder is determined by the level-name setting inserver.properties. By default, it is world. Thus, you can start a new world and toggle between the saves by simply changing this setting.

Vanilla server commands related to saving/backups:

/save/all - forces server to save. /save–off - Disables saving. This should be done before creating a backup for a running server. /save-on - re-enables saving.

Thank you! I didn't even think to disable saving while making a backup. - aedia Jun 22, 2011 14:27

i saved the server to my desktop so were will the directory be?? User14851 Nov 20, 2011, 8:22

Do you know if there is there a way to run the save-off and save-on commands from a batch job? - mpontillo Apr 26, 2012 at 14:53

@Mike If your goal is to automate backups, then you should look into plugins like Bukkit Backup or other Bukkit plugins. I would also recommend mcrcon, which allows remote commands to be run. Schism Sep 8, 2012, 19:23

A world folder should be located in the directory where you are running the server. There are all files that your server will need to run in that directory. The region folder in the world folder is the most important. It contains all of the "block information". The world directory also contains the players folder. Liberty This folder stores information about the players that have connected (inventories, etc.). (Note that the directory is only named world if you haven't changed the level-name property in server.properties.)

This information applies to both a Vanilla and Bukkit multiplayer server.

Backup the entire world directory.