[[!comment format=mdwn
 username="joey"
 subject="""comment 1"""
 date="2015-07-30T17:18:24Z"
 content="""
The -J1 is a red herring; there's no progress output for -J modes, so the
whole transfer runs quietly there.

The -J2 failure is because the rsync special remote implementation uses a
local scratch directory which is supposed to be empty. But, since it uses
the pid of the process to create the directory name, concurrently transfers
will use the same scratch directory and so interfere with one-another.
"""]]