On 11/09/2012 5:22 PM, mike cloaked wrote:
On Tue, Sep 11, 2012 at 8:06 PM, mike cloaked <mike.cloaked@xxxxxxxxx> wrote:
On Tue, Sep 11, 2012 at 7:51 PM, Jan Steffens <jan.steffens@xxxxxxxxx> wrote:
On Tue, Sep 11, 2012 at 8:27 PM, Thomas Bächler <thomas@xxxxxxxxxxxxx> wrote:
2) When chrony is not running, systemd-timedated runs periodically to
adjust the hardware clock for drift (AFAIK, not sure that is the job
that timedated does).
No. When chrony isn't running, the hwclock isn't getting adjusted at
all. The only thing systemd does on startup is warp the system clock
if and only if the RTC is running in localtime.
systemd-timedated's job is to provide a DBus interface to change
system time and date settings:
SetTime, SetTimezone, SetLocalRTC (whether RTC is in localtime),
SetNTP (whether NTP is enabled)
It's used by gnome-control-center, at least. The SetNTP call uses the
ntp-units.d directory to select an implementation.
Thank you for all the information - it seems that the key to this was
that the RTC was too far out from correct time at boot - now that I
manually set the RTC to correct time it comes up close to correct -
and then chrony synchronises a few minutes after startup. At present
tracking shows it is about 0.1 microsecs from NTP time:
System time : 0.000000106 seconds fast of NTP time
What I don't understand is why the hardware clock was not re-written
with the correctly synchronised time previously, since chrony has been
running every time I booted the system for ages?
By the way I also found another way to write the hardware clock from
within chrony which does not need the chronyd daemon to be stopped
(after spending this evening reading the detailed chrony docs!) that
you can run chronyc in a terminal, and then enter "password
mypasswordforchrony" (where the argument is the password from the
chrony keys file) and then issue the "trimrtc" command once the chrony
password has been accepted - this will then write the current system
time to the RTC, only sensible if time has been synchronised - though
the RTC is only accurate to within a second or so I believe.
I guess it would be nice to have more complete information on the
archwiki though there is full documentation on the chrony main web
page.
I think the usual response is, anyone can edit the wiki - please add
what you
think is needed.
