Another thing to consider is, say you give the Metaswitch the best cesium clock, synced via a gold-plated time synchronisation protocol that walks with God, not a virtualised time server in sight for a hundred miles.
It’s just an operating system clock. It’s going to accumulate some drift of its own pretty quickly. Frequent synchronisations can mitigate that, but not altogether perfectly, and definitely not at the timing resolution about which these hairs are being split. Where’s the payoff here? — Sent from mobile, with due apologies for brevity and errors. > On Feb 18, 2020, at 8:37 AM, Alex Balashov <[email protected]> wrote: > > That was kind of my point. You’re not going to use an operating system clock > to drive TDM or things that need BITS. For billing and logs and things like > that, what’s a few tins of milliseconds matter? And if the drift is in the > hundreds of ms due to a VM server, I would say that is “unusual”. > > — > Sent from mobile, with due apologies for brevity and errors. > >>> On Feb 18, 2020, at 8:23 AM, Mike Hammett <[email protected]> wrote: >>> >> >> Non-TDM timing things. CDRs, logs, etc. I don't have an exhaustive list, but >> I can ask. >> >> We'll have to just get a BITS service from Frontier for the TDM timing needs. >> >> >> >> ----- >> Mike Hammett >> Intelligent Computing Solutions >> http://www.ics-il.com >> >> >> >> Midwest Internet Exchange >> http://www.midwest-ix.com >> >> >> >> From: "Alex Balashov" <[email protected]> >> To: [email protected] >> Sent: Tuesday, February 18, 2020 7:19:58 AM >> Subject: Re: [VoiceOps] NTP Question >> >> I'm still going to maintain that VMs are fine in our considerable >> experience, as long as the hypervisor environment isn't "out of the >> ordinary" and your applications of NTP aren't the kinds for which >> nothing less than the precision of a cesium clock will do. What does >> Metaswitch do with its system clock? Cut CDRs? >> >> -- Alex >> >> On Tue, Feb 18, 2020 at 07:04:35AM -0600, Mike Hammett wrote: >> >> > I would love to have my own stratum one in each Frontier CO we're in. >> > Unfortunately, we don't have access to put GPS antennas on the buildings >> > and the important buildings don't have windows and have us behind multiple >> > layers of brick walls\concrete floors, so an indoor antenna isn't likely >> > to work. >> > >> > >> > Clocks that accept their information via PTP from a location where we can >> > put up a GPS antenna run into the thousands of dollars (though I am still >> > waiting on quotes), thus aren't exactly reasonably priced. >> > >> > >> > >> > >> > To seemingly conclude the thread, 3 are required, 4 or 5 are recommended. >> > VM NTP servers are to be avoided. >> > >> > >> > >> > >> > I'll roll with VMs for now while I develop a plan to have something there >> > I can use the hardware directly (no VM). I'll swap out each VM for >> > hardware when a reasonable course of action is available. >> > >> > >> > >> > >> > ----- >> > Mike Hammett >> > Intelligent Computing Solutions >> > http://www.ics-il.com >> > >> > >> > >> > Midwest Internet Exchange >> > http://www.midwest-ix.com >> > >> > >> > >> > ----- Original Message ----- >> > >> > From: "Peter Beckman" <[email protected]> >> > To: "Tim Bray" <[email protected]> >> > Cc: [email protected] >> > Sent: Monday, February 17, 2020 10:02:46 PM >> > Subject: Re: [VoiceOps] NTP Question >> > >> > Ooooh I like that one! >> > >> > The thread got a little confusing -- >> > >> > Are we talking about using NTP as a client on VMs? >> > >> > Or using VMs to run NTP servers? >> > >> > If as a server: >> > Hell NAH! Don't do it. Like everyone said, the clock available to the >> > OS isn't reliable, you don't want its drift to affect other machine's >> > clocks. >> > >> > If as a client: >> > Hell YAH! VM clocks are unreliable. Heck, we had a dedicated server that >> > had a 14 second a day drift! We used the heck out of NTP to keep that >> > sucker from losing time. >> > >> > Sort of related: I really love OVH as a hosting provider, but they offer >> > one time source, and it is in Beauharnois, Canada, even if you use their >> > Oregon US Datacenter. These NTP devices are so inexpensive to cover a >> > whole >> > datacenter, why are we introducing network latency?!? >> > >> > I am of the opinion that each physical datacenter should provide its own >> > Stratum 1 NTP source. >> > >> > Beckman >> > >> > On Tue, 18 Feb 2020, Tim Bray via VoiceOps wrote: >> > >> > > On 17/02/2020 21:52, Mike Hammett wrote: >> > >> How many NTP servers do you guys run? >> > >> I just spun up two NTP servers in different locations on this network. >> > >> Metaswitch just asked me for at least four (preferably five, or even >> > >> more). >> > >> Right now, the ones I have are just referencing the US pool. >> > >> Eventually, >> > >> they'll reference on-net GPS-backed devices. >> > > >> > > >> > > https://store.uputronics.com/index.php?route=product/product&path=60_70&product_id=92 >> > > >> > > >> > > >> > > LeoNTP server. If you want to run your own. >> > > >> > > >> > > >> > > >> > > >> > > -- >> > > Tim Bray >> > > Huddersfield, GB >> > > [email protected] >> > > +44 7966479015 >> > > >> > > >> > >> > --------------------------------------------------------------------------- >> > >> > Peter Beckman Internet Guy >> > [email protected] http://www.angryox.com/ >> > --------------------------------------------------------------------------- >> > >> > _______________________________________________ >> > VoiceOps mailing list >> > [email protected] >> > https://puck.nether.net/mailman/listinfo/voiceops >> > >> > _______________________________________________ >> > VoiceOps mailing list >> > [email protected] >> > https://puck.nether.net/mailman/listinfo/voiceops >> > >> >> > _______________________________________________ >> > VoiceOps mailing list >> > [email protected] >> > https://puck.nether.net/mailman/listinfo/voiceops >> >> >> -- >> 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/ >> _______________________________________________ >> VoiceOps mailing list >> [email protected] >> https://puck.nether.net/mailman/listinfo/voiceops >>
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