[ntp:questions] Is this normal?
hal-usenet at ip-64-139-1-69.sjc.megapath.net
Thu May 13 05:17:34 UTC 2010
In article <C430DA47D51D0C4B940F6928BAE21F4626A3F16590 at SBKMXSMB06.win.dowjones.net
"Russell, David" <David.Russell at dowjones.com> writes:
> The device is a piece of networking equipment and so I doubt that the crystal
> is temperature controlled but since it is in a data center the temperature
> and power demand is steady.
> If you could see the graph you would see that it seems to oscillate around
> -3.05 us/s over a 24 hour timeframe. The graph has a pretty nice looking
> sine wave with a 12 hour period. I was expecting that if the "true" drift
> rate were -3.05 then NTP would converge upon that value. Are you saying
> that this oscillation is typical for non-temperature (cheap) crystals or
> should the drift look more random?
The drift follows temperature. Do you have any way to measure the temperature?
> Any thoughts on validating a black box NTP process?
Setup NTP on another box and tell that box to use the black-box as a server.
Use "noselect" if you want to make sure it won't try to sync to that system.
Then turn on loopstats and peerstats. That will give you lots of data to
> I had not realized until I sent out the email that no attachments are allowed.
> Is there a way to share a graph?
Put it on the web someplace and send a URL.
These are my opinions, not necessarily my employer's. I hate spam.
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