For the backup in one minigame , what are the best method for save multiple aree in same world? My idea was to save 25 chunk in a radius and overroload they when finished the game, the are better methods and more optimized?
There are multiple ways to do this. The easiest is, as @HimbeersaftLP said, to disable auto-save and simply reload the world. But since you're using the same map for multiple games, you could for example either log the chunks that are edited on-the-go and then reset those(i.e. serializing/unserializing) or log all changes and undo them. Depends on how much effort you want to put into this, how many games & players you have and especially on how much the world is changed.
Try serialize chunks used for the game and then userialize them after restart. Changing every block manualy will take hours with php...
If you do not have the intention to save any part of the world, you could disable auto save, teleport players away from the area, unload any chunks you want to reload. The chunks will be fresh when they are loaded again when in player's view
Meh. What if all the players are in one spot of the map and the chunks on the other side are unloaded? This is not the way to go.