nanog mailing list archives

Re: NTP Issues Today


From: George Herbert <george.herbert () gmail com>
Date: Tue, 20 Nov 2012 17:14:48 -0800

As a reminder - time infrastructure is not recommended for
virtualization.  Make them physicals.


On Tue, Nov 20, 2012 at 5:03 PM, Blake Dunlap <ikiris () gmail com> wrote:
That's what happens when you just follow vendor recommendations blindly. If
you do follow that on vm's (which can actually be a good practice), make
sure they pull from your own time infrastructure, and not just the world at
large, and that those servers behave in a sane fashion with regard to time
jumps.


On Tue, Nov 20, 2012 at 6:56 PM, Darius Jahandarie <djahandarie () gmail com>wrote:

On Tue, Nov 20, 2012 at 7:49 PM, Jimmy Hess <mysidia () gmail com> wrote:
Are you sure that you are actually using NTP to set your clock?
For you to sync with 2000,  you should have had multiple confused
peers from multiple time sources;  possibly a false radio signal....

NTP by default has a panic threshold of 1000 seconds.

This  _should_   have caused NTP to execute a panic shutdown,
instead of setting the clock back  30 million seconds.

For VMWare at least, their official recommendation[1] for NTP is to

tinker panic 0

for suspend/resume reasons. I've seen it default in some places.

[1]
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006427

--
Darius Jahandarie





-- 
-george william herbert
george.herbert () gmail com


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