I'm a Linux newbie and new to this forum, so please be gentle. :-)

I've installed Virtualbox on Puppy 5.4 on a large capacity USB. It's fun, an interesting combo. When I install small virtual machines, everything works fine.
Problem is, when I try to create larger ones that exceed my memory size (3gb), halfway through the process it chokes with memory full errors because it's filling up memory instead of writing to disk.

1. Is it possible to change Puppy settings temporarily so that memory immediately flushes to disk so I can install something larger than my memory space (3gb) ?
better yet:

2. is it possible to set Puppy to flush memory to disk when the memory usage reaches a certain threshold?

Thanks in advance.

Linux memory management is more than capable. VBox fixes memory so it can't be flushed to disk - for performance presumably.
VBox is the problem, not Linux.