WARNING: storage file size reduced to.....

[rad_kam at tlen.pl]

when i run varnish i get this messages: 

WARNING: storage file size reduced to 1073741824 due to system limitations
WARNING: storage file size reduced to 11756049694 (80% of available disk space)
NB: Limiting size to 2GB on 32 bit architecture to prevent running out of
address space.  Specifiy explicit size to override.

What does it mean ?