Here is the scenario...
NFS share that is accessed every few minutes by approx 70 systems (AIX 5.3/6.1). Filesystem space is being eaten up rapidly according to df however du numbers really never change. lsof and fuser cannot see any unlinked files on either the NFS server or remote clients. Restarting nfsd does not resolve the issue. However, attempting to umount the underlying JFS2 filesystem fails (device busy) obviously but magically frees up the "used" disk space...
Any thoughts on this? 