The README and web page both include the following text:

        Durus is best suited to collections of less than a
        million instances with relatively stable state.

Where does the figure of around a million come from?  Is it just
pulled from the air, or does it stem from FileStorage having an
in-memory dictionary mapping OIDs to file positions?

I'm storing a simulation model.  Converting our largest model results
in just over 100,000 objects, so that's already 10% of the way to the
limit.  Toss in a few extra copies of the model for backups,
versioning, or experimentation, and I'll probably reach the
million-object mark fairly quickly.  Should I be worried?  Should I
start thinking about how to make FileStorage more memory-efficient?

--amk