I'm having an issue where the Nether doesn't seem to save any chunks. I'm playing on my personal SMP server, so usually I'm the only one who's actively playing.

Whenever I step into the Nether, all the blocks I have broken or placed from last time are reverted. In fact, when I enter from my Overworld portal, depending on what exact coordinate I was standing in while entering, alters the orientation of the Nether portal, but I'm still in the same location. (Which suggests a new portal is created every time I enter!) Also, if I travel too far away from my Nether portal, while I'm in the Nether, I'll return to find my Nether portal gone! AND, none of these issues crop up with the Overworld!

A little background about my server: I'm running the server from within a ramdisk. I have dedicated 4096MB for the server's heap (-Xmx4096M), and the ramdisk holding the server data has a max size of 2048MB. My system ram is 16GB and I typically have anywhere from 8GB to 10GB free at any moment in time, according to "free -m". The amount of space taken up by the ramdisk is around 5%, according to "df -h". I do not save any data from the ramdisk to the hard disk until I stop the server completely. All of this information suggests to me that my ramdisk setup is NOT PART OF THE ISSUE.

How to Recreate:
1. Start a Minecraft server.
2. Log in to the server.
3. Create a Nether portal.
4. Enter the portal, place a block down nearby, then go back to Overworld.
5. Return to the Nether. If the block is gone, then the chunk wasn't saved.