Comment # 132 on bug 1063638 from Tasik B

Don't want to create a new report or new post in the forum, people comments
above says a lot. I will describe my situation:
openSUSE Leap 15, KDE Plasma, Xeon E5-2665, decent SSD for the root file
system.
File system by default as suggested on install so its BTRFS root file system
all other disks as ext4. Usually, overnight keeping PC on sleep mode, but when
waking up and "btrfs balance start -v 50" kicks in seems that PC is frozen and
after single Ctrl+Alt+Backspace happens hard restart. Or if the process starts
when logged in then its impossible to do anything, everything freezes and
unusable. 
I think there is no such an issue on no other OS, at least. Maybe this process
needs to have lover priority or need a slightly different design? Just don't
know for how long more I will forgive to opensuse...