| 答复: [chrony-users] Multiple Clock Sources Cannot Be Synchronized |
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I don't know if it is feasible. Add a configuration option or default behavior. In the scenario of multiple clock sources, if the difference between more than 50% of the clock sources reaches a certain value, they are considered reliable and can be marked as * or + instead of x.
For example, there are three clock sources A, B, and C. If the difference between A and B is 50 ms and that between A and C and C is 500 ms, can A and B be considered correct? Although this may be incorrect, C is not ruled out. However, the probability that both clock sources are abnormal should be less than the probability that one clock source is abnormal. Unless it's abnormal in the first place.
If multiple clock sources are configured, the system considers that the clock source may change or other situations occur. If the trust field is configured for one of the clock sources, the system does not configure multiple clock sources when the clock source is abnormal.
-----邮件原件-----
发件人: chengyechun
发送时间: 2024年10月25日 9:14
收件人: chrony-users@xxxxxxxxxxxxxxxxxxxx
主题: 答复: [chrony-users] Multiple Clock Sources Cannot Be Synchronized
Thank you for your reply. There is another question. What is the difference between two clock sources to make them trust each other? After all, the difference of 65 ms can be ignored in some scenarios.
-----邮件原件-----
发件人: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
发送时间: 2024年10月24日 21:29
收件人: chrony-users@xxxxxxxxxxxxxxxxxxxx
主题: Re: [chrony-users] Multiple Clock Sources Cannot Be Synchronized
On Thu, Oct 24, 2024 at 01:02:40PM +0000, chengyechun wrote:
> MS Name/IP address Stratum Poll Reach LastRx Last sample
>
> ======================================================================
> =========
>
> ^x 9.82.178.244 10 2 17 1 +3788ns[+3788ns] +/- 147us
>
> ^x 9.82.165.239 10 2 17 1 -65ms[ -65ms] +/- 152us
These two sources don't agree with each other. They are about 65 milliseconds apart. chronyd doesn't know which one (if any) is correct. That's why normally is recommended to have at least three sources. You can mark one with the "trust" option to force chronyd to select it.
--
Miroslav Lichvar
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