Процесс Rsync долго ждет после завершения

Краткий ответ :Попробуйте rsync --outbuf=L, чтобы получить прогресс в реальном времени.

Это может быть буферизация вывода, которая упоминается на страницах rsync manв переключателе --bwlimitдля ограничения пропускной способности:

--bwlimit=RATE

(...)

Due to the internal buffering of data, the --progress option may not be an accurate reflection on how fast the data is being sent. This is because some files can show up as being rapidly sent when the data is quickly buffered, while other can show up as very slow when the flushing of the output buffer occurs. This may be fixed in a future version.

Переключатель --outbuf:

--outbuf=MODE This sets the output buffering mode. The mode can be None (aka Unbuffered), Line, or Block (aka Full). You may specify as little as a single letter for the mode, and use upper or lower case. The main use of this option is to change Full buffering to Line buffering when rsync's output is going to a file or pipe.