Sorry, Art, I have no answers.

However, I just have to ask: Why on Earth are you trying to do this? Even
if you can solve the mystery, are you really going to host a database over
200GB in that environment? Aren't you a bit worried that some other gotcha
is going to appear at some point?

From what I can see you can already increase the DB from 70GB to 198GB. Do
you really want to increase it beyond that in a machine environment which
is clearly having trouble? I always thought databases that big belonged in
environments which were designed to handle them (e. g. Solaris).