Server Resetting itself, losing recent progress and items.

I updated everything on my server this morning, and then after returning later today, players are complaining of the server resetting itself every few minutes, crashing and then, upon relogging in, having lost all of their recent progress.

I'm running this server on a RAMdisk of about 700 megabytes, so I'm wondering if it's because the server doesn't have enough room to expand and save changes, though the files never got within a few hundred MB of full, so I'm not sure.

Running Essentials, Permissions, WorldGuard, WorldEdit, iChat, MagicCarpet, Mywarp, Myhome, TelePlus, MCbans, and Guardian, all updated to latest (Except for maybe essentials, since it's broken.)

Any ideas on what's causing it? I'm making sure the RAMdisk has plenty of room, and updating again, and we'll see if it continues.

UPDATE: I'm running the server on a different computer now, the lag is gone, but several chunks have completely erased all user data from them, while not others. The landscape is the same as it was when we started the map, just without the user-placed blocks there. Attempting to restore to a previous backup...

 

If the size of your ramdisk is bigger than your world by a couple hundred MB's, its not you ramdisk.

Have you removed your plugins and tried it on plain CraftBukkit?

 

No, I haven't. Looking at Bamboo, it shows the last several builds of CraftBukkit to be broken, including the one I updated to earlier today (I think.), so I'm reverting back to the last working build, and we'll see what happens now.

 

Well, yes, make sure you aren't running an unstable build. 141 works well for me.

 

Reloaded with a stable build, and now lag is becoming horrendous. Nothing else is running on the computer, settings are as normal as they have ever been, but there's about three minute chat lag, and players are complaining of every other kind of lag as well.