[ntp:questions] How can i make sure that how much time ntp is adjusting one day
michael.cook at sfr.fr
Tue Aug 7 09:03:48 UTC 2018
> Le 6 août 2018 à 03:06, William Unruh <unruh at invalid.ca> a écrit :
> On 2018-08-05, aashish.chugh at fonantrix.com <aashish.chugh at fonantrix.com> wrote:
>> I am facing time drifting problem in my production env.
When face with this or any problem you should measure it BEFORE applying corrections. I have seen many admins just add NTP, only to find that the clock drift was too great to be corrected by NTP.
NTP will bail out if it finds a drift of over 500ppm.
Check the value measured before correcting and see if it is within the server manufactures clock spec. You may have a bad board or need a firmware update.
It may also depend on the hardware context. Is your prod running in a stand alone server or is it in a virtual environment (container). There are tight constraints for running time critical stuff in containers.
Maybe your server is modifying its cpu clock frequencies depending on load. You will need to check and stop that.
>> I install ntp on my linux server and configure that.
>> i enable the ntp, how can end of the day i can get the total time which ntp adjusted.
As said by others , NTP alters the clock frequency rather than setting the clock (unless way out).
If you run « ntpq -c rv » you will see a variable labeled « frequency » which gives the clock drift that NTP is correcting for at any one time.
The best way to evaluate this over long periods this is to enable stats logging and graph the loopstats drift frequency data.
>> when i execute ntpstat command i can see following output
>> synchronised to NTP server (169.254.169.123) at stratum 4
>> time correct to within 9 ms
>> polling server every 8 s
> That poll interval is really short, and if you are getting the time from a
> server that you do not control, they could get really really annoyed with you
> and cut you off.
> That is a link local address, so I do not know what it is you are using as a
> server. Could you post your ntp.conf file.
>> is there is anything need to do.
> Use a decent server?
>> Please help.
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Don’t worry about how powerful the machines are. Worry about who the machines are giving power to.
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