Re: [chrony-users] Timeout for initstepslew?

[Zack Shivers <zack@xxxxxxxxx>]

Sure, I'd be happy to tell you about the application.

Hardware:
host1 = Computer running chrony as NTP server
host2 = Computer running chrony as NTP client

Goal: Reliably sync the local time of host1 to host2, achieving sync
between system times as quickly as possible.

Assumptions:
- There are only two machines in the system
- Boot time and order is not guaranteed. Generally, both machines will
come up at about the same time.
- Access to internet is not guaranteed, and may take too long to come
up, therefore solution should not rely on non-local servers.
- Absolute time accuracy to external servers is not required. Only the
system time offset between host1 and host2 matters.
- The system time offset between machines must go below some threshold
as quickly as possible
- Stepping the clock at startup is preferred as it reduces total time to sync

I ask about the timeout on initstepslew is that the problem would be
solved if I could set a much longer timeout than 10 seconds. The
makestep option could work instead, but I've seen issues using this as
well that I will post about later.

RTC might be sufficient to get a reasonable sync time. Can you suggest
a configuration that might work?

On Mon, Sep 23, 2019 at 4:44 PM Bill Unruh <unruh@xxxxxxxxxxxxxx> wrote:
>
>   If it is not there in10 sec,
> why should it be there later? Find a more reliable source, use the RTC,
> or use chrony's ability to read file times to set the intial time. Why not use
> whatever the source  is you will use to discipline the system clock via
> chrony. Perhaps if you told us what you want to do,  suggestions for accomplishing
> that will be forthcoming.
>
> William G. Unruh __| Canadian Institute for|____ Tel: +1(604)822-3273
> Physics&Astronomy _|___ Advanced Research _|____ Fax: +1(604)822-5324
> UBC, Vancouver,BC _|_ Program in Cosmology |____ unruh@xxxxxxxxxxxxxx
> Canada V6T 1Z1 ____|____ and Gravity ______|_ www.theory.physics.ubc.ca/
>
> On Mon, 23 Sep 2019, Zack Shivers wrote:
>
> > Is it possible to select how long chrony will wait for the NTP server
> > specified in a initstepslew line?
> >
> > With this configuration, which I'm using to sync to a locally networked server:
> > initstepslew 0.1 192.168.0.2
> >
> > I see that the service will log the following if the server is unreachable:
> > No suitable source for initstepslew
> >
> > This occurs at 10 seconds after chrony starts up. Is there a way to
> > increase this time?
> >
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> >



-- 

Zack Shivers
Electrical / Embedded Systems Engineer

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