| Re: [chrony-users] time.google.com crash chronyd |
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On Sun, 6 May 2018, Alvaro G. M. wrote:
On Sun, May 06, 2018 at 01:54:31PM +0200, Nicolas Embriz wrote:
For an unknown reasons when using time.google.com chronyd don’t stat but if
I use for example “time.apple.com” it works, this is the output I get when
using chronyd -d:
I can't help you with that, but I think you should be aware that
time.google.com behaviour is non standard, so you may not want to use it.
https://github.com/systemd/systemd/issues/437
Just to be clear, google treats leapseconds in a non-standard way. ntpd and
chrony step the clock over a leapsecond-- either forward or backwark at the
leapsecond. Google however smears the leapsecond before and after the
leapsecond time, over about an hour. If something sets the leapsecond flag,
then google time will start smearing the leapsecond an hour before (eg,
speeding up their clocks by about 150PPM) an hour before the leapsecond should
occur, and up to an hour afterwards, but without putting in a leapsecond. Now
if other time source sets the leapsecond flag on your chrony, then there is a
danger that the leapsecond will also be applied as a step by chrony.
completely messing things up around the leapsecond time.
So, don't use google. Use pool.ntp.org or get yourself a timeing gps (gps with
PPS)and set your system up as a stratum 1 time using gps with pps if correct
timing is important to you. (pool, since it uses volunteered servers, can be a
less than exact in its time delivery-- you should not expect better than
millisecond accurcy from the pool)
(You can ignore all the systemd flame, just the main post is enough and has
the references you may need to further investigate this thing).
Well, since it is very likely that the OP got his default from systemd, it is
not clear that the systemd comments are inappropriate. I certainly thing it is
inappropriate for systemd to use google as their default. Users are going to
read "default" as "recommended"-- why would anyone be so irresponsible as to
use a default which is defective. Of course systemd may have altered this
since 2015.
Nope. From timesyncd.conf
#FallbackNTP=time1.google.com time2.google.com time3.google.com time4.google.com
It is commented out, but this certainly is silly. (It might be mageia that
commented it out, or it may come directly from systemd)
And in man timesyncd.conf
"If this option is not given, a compiled-in list of NTP servers is used
instead"
And I suspect it is google's server that is compiled in. This is really
irresponsible.
So, the question is -- where did the OP get his "timeX.google.com" from that
he is using.
Best luck!
--
Alvaro G. M.
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