I would like to say a word or two about the /usr filesystem in AIX systems in general:

in most systems haveing the /usr filesystem filled to capacity is risky if not even desastrous. Not so in AIX systems. AIX software packages are usually installed in installp format (aka ".bff-files") and installp, AIX' package manager, can increase the filesystem size automatically to accomodate exactly what is being installed. Have a look at the man page of the "installp" or the "geninstall" command for details.

Because of this it is usually a waste of space to increase "/usr", because when this space would really be needed it will be assigned automatically anyways. The only exception is when software not properly packaged is installed. I suggest repackaging it first before installing in production environments as much as this is possible (ideally, if the software installation is only copying files/directories somewhere the the repackaging is done in a few minutes).

Aside from installing software /usr is very rarely written to and its content is usually static, so you don't need to reserve space for eventualities.

I hope this helps.

bakunin