Bukkit

• If your server constantly lags from players exploring outside of the world's current boundaries but you have plenty of disk space...
• If you need a large world to test another plugin on (such as a map renderer)...
• If you just like generating things because you like the sound of your processor crying for help...

...you probably want to use this plugin.

Simply put, it generates regions of your map. It can't get much simpler than that.

There are a few safety features built in:

• When your server has less than 10MB of memory left, it waits before trying to generate any more chunks.
• No players are allowed on the server during generation.
• Every tick, only a 3x3 grid of chunks is loaded, saved, and unloaded, giving the file system time to catch up while still finishing in a reasonable amount of time.
• The generation process will wait for chunks to be saved if more than 200 are waiting in the queue to avoid running out of memory.
• If a generation command would generate more than 16GB of data, it is prevented.

Commands

There are currently three commands usable in the GenerateRegion plugin:

• /generateregion worldname x z
• /generateregion worldname startX startZ endX endZ
• /generateregion progress

The first generates a single region, the second allows you to generate multiple regions in one command, and the third allows you to get a progress report and an estimate of remaining time.

Keep in mind that the units in these commands are regions, not blocks or chunks. If you need help converting between these units, I suggest using Dinnerbone's Coordinate Tools. Regions are quite large - if you stand in the middle of one, even on the highest allowed view range, you will not be able to see any others.