Handy one liners

Find deleted files

Checking for Deleted Files Held Open in UFS File Systems


To 'find' the particular offending process(es) with open but deleted files you can use

find /proc/*/fd -type f -links 0 -exec ls -l {} \;

which looks for files with zero links, i.e. that have been deleted but a running process still has the file open.
Using the PID from the  /proc/<PID>/fd/xxxxx names returned you can determine if the process can be restarted without a server reboot.