Server crash and loss of buildings

So basically our server has crashed twice now and each time in a small radius around the spawn point all the buildings have reset back to the natural forest that exsisted there before. For example, we had spent a week building a small village, with a house each and a train station, instead of finding this when we logged back in, it was back to the original state.

The odd thing we can't understand, is how everything else in the server is still intact, for example, a castle near the outside of the world. One of us had built a dragon in the sky near spawn, the dragon was still there, but had been beheaded (which, as amusing as it sounds, irritated the owner).

To the point, is there a way to stop it from doing this, or is there plugin or something? I've tried googling the problem, with not much luck.

 

What's your server.properties?

 

#Minecraft server properties
#Thu Nov 08 18:29:13 CET 2012
generator-settings=
allow-nether=true
level-name=world
enable-query=false
allow-flight=false
server-port=25565
level-type=DEFAULT
enable-rcon=false
level-seed=
server-ip=94.23.159.19
max-build-height=256
spawn-npcs=true
white-list=false
spawn-animals=true
snooper-enabled=true
hardcore=false
texture-pack=
Minecraft=server properties
online-mode=true
pvp=true
difficulty=1
server-name=Unknown Server
gamemode=0
max-players=20
spawn-monsters=true
view-distance=10
generate-structures=true
spawn-protection=0
motd=A Minecraft Server


(Sorry, I don't know how to put it into the console window people do)

 

The reason you see that some areas are rolled back and others are not is because some of the chunks are actually saving properly. When a chunk unloads (because no one has been in it for awhile) it will save what ever data has changed to the hard drive.

If a chunk doesn't unload, whether it be a plugin keeping it loaded or w/e, it wont save until you run a /save-all comamnd or if you shut down the server using /stop. Both of those will save world data and player data to the hard drive no matter what.

Now, if your server were to crash before the chunks that are still loaded are saved then they will go back to the state they are in from the hard drive. That could be ever since you last restarted the server.

To prevent this from happening in the future I recommend you use some sort of a script to run a save-all command every x number of minutes. Even every hour is better than not doing it all. This should stop your worlds from being rolled back, but you have bigger issues if you are crashing like you mentioned.

Please post anything from your server.log that happened around the time of these crashes. We can see if we can narrow down the cause of the crash.

 

This message poppped up 4 to 5 times before it went down.

[WARNING] Can't keep up! Did the system time change, or is the server overloaded?

A little later in the log it shows the server restarting all the plugins and etc like it did the very first time I launched.

 

That really doesn't tell me anything at all. Please use http://pastebin.com to post your server.log