Quicksave-Quickload Addon for CubicChunks

Instantly restore Minecraft's state from a single checkpoint in seconds. This functionality is available in both single-player and multiplayer modes.

On the server use the command /q [save|load]

In the client use buttons in the pause menu or similar commands.

The most efficient way to save memory is frequent progress saving. Loading and saving do not affect players who are offline. When moving to another dimension after saving, you will be automatically returned back. All saves are preserved between gaming sessions.