Add options to limit space?

[markcurtis1970]

I noticed on a standard ctool node I'd run out of space, for example:

-rw-r--r-- 1 automaton automaton  32G Sep 19 14:43 seqread-raw-data-32G

Could we have an option to limit size of test or if not more simply have the README .md updated to say how much disk space you need?