First of all, the best method (IMO) for space management in a shared resource is the introduction of individual quotas. Be proactive instead of reactive. Second, to find the files of all users in a given filesystem, you need to have the permissions to read their directories, so you need to take a look at the umask setting(s) of the users, and which are their primary groups. Now, if you allow users access to other users workspaces, you degrade the overall security of the system. My preferred solution is to have a script running periodically from the superuser's crontab (that eleminates the permission problem) and place the result in a dedicated location where only the (system or data warehouse) administrators have access to (that reduces the security problem). From there, you can process the data further. Or you could do the treshold detection in the script itself (keep in mind that AIX is, like all UNIXes, extremely powerful out of the box and provides multiple scripting options like perl or python in addition to just bash) and also send the mails from there.
... View more
