[VoiceOps] [External] Re: [External] Re: [External] NTP Question

[Hunter Fuller]

I wouldn't call it incredibly oversubscribed, though we are getting a
little close on memory these days.

http://hf0002.uah.edu/sharex/chrome_nj0IR7SmQr.png

We would have pursued it more, but after reading that the general
wisdom was to not do it, we just stopped doing it, and things got
better, and I never thought about it again until now. :)

But I could see how it would be a problem in a fully virtualized
environment. Maybe a Raspberry Pi with an RTC module could be an
interesting low-cost/low-maintenance NTP box. Easy to have 4 of them
when they're $50 per box.

On Mon, Feb 17, 2020 at 4:15 PM Alex Balashov <abalashov at evaristesys.com> wrote:
>
> Interesting. I'm thinking there's something else off there. Perhaps the
> hypervisor is incredibly oversubscribed?
>
> On Mon, Feb 17, 2020 at 04:12:59PM -0600, Hunter Fuller wrote:
>
> > I wouldn't say we need it to be "really precise," but we do need it
> > within a couple of seconds, and on ESXi 6 we were seeing boxes as far
> > as 500ms off. It may not apply to all VM environments, so I guess it
> > could be worth testing. But it certainly scared me off. With physical
> > NTP servers we achieve within 10ms generally.
> >
> > On Mon, Feb 17, 2020 at 4:09 PM Alex Balashov <abalashov at evaristesys.com> wrote:
> > >
> > > On Mon, Feb 17, 2020 at 04:00:25PM -0600, Hunter Fuller wrote:
> > >
> > > > On Mon, Feb 17, 2020 at 3:57 PM Mike Hammett <voiceops at ics-il.net>
> > > > wrote:
> > > > > Is having four VMs running NTP a ridiculous proposition (well, other
> > > > > than resources, which it'll consume very little)?
> > > >
> > > > Yes. NTP servers should never run in VMs.
> > >
> > > I don't know about that. The nature of virtualisation has changed
> > > greatly over the past decade; VMs have gone from being a kludgy and slow
> > > software-emulated environment to almost a first-class CPU guest, thanks
> > > to paravirtualisation and supporting CPU features.
> > >
> > > And NTP is specifically designed for latency in a rather general sense.
> > >
> > > If you're using NTP for any really precise timing calibration, that's
> > > the wrong vehicle, anyway.
> > >
> > > -- Alex
> > >
> > > --
> > > Alex Balashov | Principal | Evariste Systems LLC
> > >
> > > Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
> > > Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
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>
> --
> Alex Balashov | Principal | Evariste Systems LLC
>
> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/
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