[ntp:questions] Hopelessly broken clock?

Richard B. Gilbert rgilbert88 at comcast.net
Sun Nov 16 03:38:12 UTC 2008

Chris Richmond wrote:
> I'm trying to set up ntp on a new Core2 Duo box running Fredora Core9.
> It appears that it's local clock runs several seconds an hour fast.  I'm
> basing this on running ntpdate against the existing box I have running
> ntp with pps.  It reports skewing the clock by seconds even after just
> a few minutes.
> Also, ntpq data shows the jitter as always 0.997, and the offset goes
> nuts right away.  The poll and reach look like they are working, but
> the time just gets away really fast.
> I have another box with the same O/S install and ntp config, and it locks
> up right away just fine, so I suspect it's a hardware issue, not a
> config problem.
> I've tried to read through the offical docs on the NTP web site on
> diagnosing problems, but can't make sense of what some of the
> instructions mean. What's missing are examples of what actually
> needs to happen.
> In any case, if the actual box's clock is that far off, is it a lost
> cause as a time keeper?
> Can I make ntptime correct the kernel's clock enough to get this
> to work?  If so, how, and can this be done in the bootup scripts?
> Thx, Chris

What does your drift file say?  If the drift is greater than 500 PPM,
the clock is sufficiently bad that ntpd can't discipline it.  Depending 
on what O/S you are running, you MAY be able to correct this or maybe 
not.  A typical drift value is less than 50 PPM.

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