[ntp:questions] Virtual Linux looses sync?

Steve Kostecke kostecke at ntp.org
Fri Oct 7 13:42:39 UTC 2011


On 2011-10-07, Tom <zihav at yahoo.com> wrote:

> We have a Linux system running on VMWare that for some reason keeps
> loosing the lock (the clock drifts quite a bit 30 seconds or more) and
> then will re-lock.

Please see the vendor documentation at
http://www.vmware.com/pdf/vmware_timekeeping.pdf for their recommended
best practices.

It would be helpful if you could post your NTP version as well as your
ntp.conf (without the commented out, or "#", lines)

> I've double checked the ntp.conf file, but don't see any differences
> from our other Linux systems. Even when it's not locked it can see the
> master:
>
> # ntpq -p
>  remote        refid       st t when poll reach delay offset  jitter
>======================================================================
> *LOCAL(0)      .LOCL.      10 l   19   64  377  0.000  0.000   0.001
>  tewks-arb...  192.5.41.40  2 u   20  512  377  0.176 409.321 27741.4

The Undisciplined Local Clock (aka "LOCAL" or ".LOCL.") is not, as often
misstated, a "backup time source" for leaf-node (i.e. client only)
systems.

The Undisciplined Local Clock should only be used in situations where an
ntpd must be able to serve time to others even when all real time
sources are unreachable, or when the kernel clock is disciplined by some
other means.

As such the Undisciplined Local Clock does not belong here and is only
exacerbating your problem.

-- 
Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/



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