TL;DR; why Debian becomes slow after long duration low activity but Ubuntu doesn't (and how to fix it)?
I've been using Ubuntu for a long time (up to 16.04), recently I changed to Debian (8 for a couple of days and 9 now). One frustrating thing I have experienced with it is that, when I leave the system up for a day/night doing some low activity (network intensive) work, when I want to (interactively) use the system again, it is highly unresponsive (for quite a long time but eventually it reaches an usable state).
I don't believe it is a desktop environment thing because I experienced the same behavior with Gnome 3 and now in KDE.
I came across these threads:
- Linux slows down after long uptime
- Apps are slow the first time they open or after being idle for a while
And they blame the swappiness and the amount of RAM. However I've checked the swappiness in one of my machines running Ubuntu (16.04) and they have it set to 60 (same as the one with Debian) and have considerably less memory than this one too.
Also, with the same hardware, running Ubuntu, I never experienced such behavior (and I have done "exactly" the same experience described before).
So...my question is, what do Ubuntu does different than Debian that may prevent the described behavior? Or it maybe has to do with the kernel version (Debian's 4.9.0-3-amd64 VS Ubuntu's 4.4.0-83-generic)?
As a reference, the hardware is a Samsung Ativ Book 8 (8 GB RAM).
Also, the processing being done during the low activity period is a Dropbox sync running inside a docker (and some status monitoring running inside the docker and printing to stdout every 2 min).
