Bug#755722: systemd must sync systemclock to RTC on shutdown

[Roger Lynn]

On 13/02/2015 06:54, Martin Pitt wrote:
> Control: severity -1 normal
> 
> I still disagree with critical:
> 
>  - If the hardware clock is so broken that at the next boot it has an
>    earlier time than on the previous boot/ntpdate, then writing it
>    once more at shutdown isn't going to entirely fix this problem, as
>    it will again go sufficiently wrong if you don't reboot immediately
>    but after some time.

A good hardware clock can easily lose many minutes over a year. A not
particularly bad one could lose an hour over a year and several minutes over
a month. That is not at all broken and will cause time to go backwards on
every reboot. Every machine with a hardware clock that does not run fast
will eventually run into this problem every time they reboot if the hardware
clock has not been written since installation, especially if they boot quickly.

The user can not easily monitor the status of the hardware clock and will
see that the time on the computer appears to be accurate. There is no reason
to assume that the hardware clock is more accurate when the user can only
monitor the system clock.

Roger