Upon further review of the issue, we found that the issue with the
paging is because of what we believe is a bug in Informix 9.4 FC7. We
have only three systems still running that version, and the symptom we
see there is that the memory is not released after completing certain
procedures in the Informix database.

The paging space issue seems to be more noticeable on the one server,
as that one does a lot of information warehouse data analysis, which
use the "questionable" routines that were causing the problem.

Temporary solution: Run "onmode -F" on the instance to free up memory
segments that were reserved but not released properly.

Permanent solution: Upgrade to Informix 10 or higher. We tested the
same scenario on that platform and it worked fine. It does not chew up
memory and start swapping it after some time.

So it ends up it is not really an AIX issue, but hope this may help
someone who is running Informix on AIX, or the AIX admin can advise
their Infromix DBA that it is clearly a RDBMS issue causing the
problem.

SteveN