After a inplace upgrade 5.1.8 to 6.5.4a last weekend without any problem, I
saw the following message on the server console this morning:

20.11.2006 10.11.21 : LFS-5.12-73 [nmID=A0004]
Volume MAILSERVER/VOL1 out of disk space.
There are no deleted files using disk space.

That's a 28 GB traditional volume with 22 GB used and 6 GB free. eDirectory
Entries are also 23% available.
So what can cause that?

Thanx for any suggestions.