Markus Schaaf <markuschaaf@xxxxxxxxx> wrote: > Am 23.01.23 um 17:40 schrieb Friedrich Romstedt: > > > Can you maybe detail a little the actual symptoms of these unsafe > > shutdowns? > > The post I linked to explains the problem rather well. Devices > are sent a stop/shutdown message shortly before the system is > losing power. The devices acknowledge these messages Can it be the acknowledgement means `I got your message', but not `I read it, and am ready for a shutdown'? Just a guess. I haven't looked at it in depth. -- u34 > and the > system is halted, rebooted or powered off. What I can see, > despite everything working as written, is that filesystems that > care to report it (f2fs) sometimes are left in a state like after > a sudden power loss, while the system reported a proper shutdown. > Other filesystems are less noisy about this, simply replaying > their (imcomplete) journal, and rarely losing some files. I have > seen the latter after a heavy `pacman -Syu` followed by an > immediate shutdown. > > One might wonder why this happens, after a disk acknowledged the > shutdown message. I can only speculate. Of course the > message/acknowledgement cycle comes with a timeout. Maybe it is > sometimes too short for disks with large RAM-caches or > complicated data management schemes. This is only a problem when > write caches are filled before power-off, so developers may opt > to send that acknowledgement in time and hope for the best, > instead of triggering error messages that may make the drive look > bad. > > As this is a race condition depending on a lot of random timings > and cheap SSDs have no RAM nowadays, this all is probably not a > real problem to most users. > > BR
