I have in my Arch Linux-running laptop an SSD and an HDD; the latter I use seldom. It is mounted as /mnt/sdb5 and configured to spin down proactively when on battery (/etc/default/tlp, ...
On other operating systems, there are ways to see what process or event woke them from suspend. I leave my laptop often for multiple days in suspend, sometimes to find that it has woken itself up and ...
I'm using archlinux. It never auto-suspend before a recent system upgrade(maybe I updated the kernel?). I think it is related to laptop-mode or acpid, so I stop them: /etc/rc.d/laptop-mode stop ...
The only way I can wake up my laptop (HP Elitebook 8460p) from suspend is by pressing the power button. Neither the built-in keyboard/mouse nor the external ones (connected via USB) wake the laptop ...