"the only notable creation/deletion overhead of IO is only during start up or shutdown of fail2ban"
I am not sure on that though -- we also have those ```actioncheck``` commands etc

Now I wonder (just thinking out loud) -- may be this swallowing/redirection should indeed be optional -- i.e. an option to the action (and/or if debug level), and otherwise just keep dumping everything to stdout as it did before (stdout=None, ...)?

eventually someone needs to start crafting a benchmark battery.
May be using https://github.com/pydata/vbench  or do you know something more established ?
I could find a host where to exercise it "consistently"