I've done a search for my problem but could not find anything, so please forgive me if I've missed it.

My problem is that my drive is reporting that its 97% full. Doing some initial checks, I can't find any reason why it would say this as my drive is 250GB in size but only about 83GB is being used.
I'm using Ubuntu 9.04 server 32bit. The drive is a standard Maxtor SATA drive.
As you can see, its saying its almost full. But doing a check on what directories are using what, it only shows that 83% is being used.
A further break down shows:
Doing a manual check of du -h shows basically the same.
Directories within the / partition
So I"m looking for help on this one. I"m not running anything weird, just a normal server running web, email, etc. Can someone point me in the right direction that can help me find and clear this? Thank you very much in advance.

Yes, I've done those commands before. They always come up and show the drive space being used is 83GB, not the 209GB that the df command shows.

Any other ideas on how to sleuth out the usage?

Have you recently moved any mount points? Once I moved /home to a new partition and forgot to delete all the files before mounting the new /home directory. Did that make any sense?

I'll try to explain better, just in case. I installed linux with a single / partition that then started running out of space. /home had 15GB of files in it. Then I created a mount point /mnt/newhome on a new disk (like /dev/sdb1) and copied all the files over to newhome. Then I changed fstab and remounted /dev/sdb1 as /home without deleting the files on the old /home directory. So /dev/sda1 was still "using" the 15GB, even though it wasn't shown. So I had to unmount the new home directory, change fstab back, delete all the files from /home, then remount /dev/sdb1 as /home. Then the 15GB were free again.

I understand, but I'm pretty sure that i didn't mount / remount / unmount anything. In fact, everything was fine until I tried to copy a file over to it and it ran out of space. In checking, I found the drive reporting 97% full, but could only account for 83GB of the 250GB total space.

There must be a simple answer to this......but: More often than I can count, I have solved such things by brute force--in the limit, by reinstalling the system.

You certainly could copy everything to another drive, and then see what's left......AND--I assume you have ruled out hidden files or directories.

How about sparse files: see --appparent-size here http://linux.die.net/man/1/du
Another thing to check (although prob not the answer) is inode usage (-i) http://linux.die.net/man/1/df