David, so you know Docker on osx really runs a Linux VM on your mac and connects to it to run container programs. The problem we are seeing here is that the Linux OS function used by CockroachDB to retrieve the “free space” information returns the wrong information.
I am pretty confident that this problem also exists regardless of which database you use. However, chances are that mysql/postgres do not use the same OS function, or that you don’t happen to “see” them using the wrong results (what part of mysql/postgres is really interested in the amount of free space? is there some web ui embedded into mysql/postgres that shows you this information? I don’t recall.)
So yes probably the problem is not specific to CockroachDB.
This doesn’t mean we shouldn’t try to work around it.