I would like to look at my BM 3.6 log (if it exists) to get an idea of how
I'd like to configure disk space for my soon-to-be BM 3.8 server. What
file(s) should I look for and where?

Will a dedicated log volume periodically downsize itself when it runs out of
disk space, like a cache volume will, or will I need to set up a grooming
policy to avoid out-of-disk-space error messages.