I have just installed Clear Linux (desktop live) and started to copy some big files back from my backup on an external USB HDD. To my not-so-pleasant surprise, I was unable to use my computer for the duration of the transfer.
So I started to investigate and found out that it is (mostly) due to the settings of dirty memory. After installation the files contained this:
/proc/sys/vm/dirty_background_bytes -> 0 /proc/sys/vm/dirty_bytes -> 0 /proc/sys/vm/dirty_ratio -> 50 /proc/sys/vm/dirty_background_ratio -> 5
First I solved the problem by lowering the ration to 1 in
dirty_ratio but then I read this article and saw that the mighty Linus considered setting ratio values old-fashioned in 2013, and started wondering - why does the most progressive Linux distribution defaults to such settings?
Currently, I have set
dirty_background_bytes to 8 MB, and
dirty_bytes to 16 MB (and ratios to 0) which is probably a bit too low as the speed is slower but the difference in responsiveness is not noticeable from the ratios set to 1.