<html><head><style type='text/css'>p { margin: 0; }</style></head><body><div style='font-family: arial,helvetica,sans-serif; font-size: 10pt; color: #000000'>I was looking to get a couple Pis and use them to feed the VMs, but we don't currently have many (any) places on our fiber plant to locate even a Pi GPS box. That'll change in the coming months, but that's not now.<div><br></div><div>BTW: It seems like it's about $50 per hat to add GPS to a Pi, so we're probably looking at $100/box... not that it's prohibitive then either.<br><br><div><span name="x"></span><br><br>-----<br>Mike Hammett<br>Intelligent Computing Solutions<br>http://www.ics-il.com<br><br><br><br>Midwest Internet Exchange<br>http://www.midwest-ix.com<br><br><span name="x"></span><br></div><br><hr id="zwchr"><div style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><b>From: </b>"Hunter Fuller" <hf0002+nanog@uah.edu><br><b>To: </b>"Alex Balashov" <abalashov@evaristesys.com><br><b>Cc: </b>"VoiceOps" <voiceops@voiceops.org><br><b>Sent: </b>Monday, February 17, 2020 4:19:27 PM<br><b>Subject: </b>Re: [VoiceOps] [External] Re: [External] Re: [External] NTP Question<br><br>I wouldn't call it incredibly oversubscribed, though we are getting a<br>little close on memory these days.<br><br>http://hf0002.uah.edu/sharex/chrome_nj0IR7SmQr.png<br><br>We would have pursued it more, but after reading that the general<br>wisdom was to not do it, we just stopped doing it, and things got<br>better, and I never thought about it again until now. :)<br><br>But I could see how it would be a problem in a fully virtualized<br>environment. Maybe a Raspberry Pi with an RTC module could be an<br>interesting low-cost/low-maintenance NTP box. Easy to have 4 of them<br>when they're $50 per box.<br><br>On Mon, Feb 17, 2020 at 4:15 PM Alex Balashov <abalashov@evaristesys.com> wrote:<br>><br>> Interesting. I'm thinking there's something else off there. Perhaps the<br>> hypervisor is incredibly oversubscribed?<br>><br>> On Mon, Feb 17, 2020 at 04:12:59PM -0600, Hunter Fuller wrote:<br>><br>> > I wouldn't say we need it to be "really precise," but we do need it<br>> > within a couple of seconds, and on ESXi 6 we were seeing boxes as far<br>> > as 500ms off. It may not apply to all VM environments, so I guess it<br>> > could be worth testing. But it certainly scared me off. With physical<br>> > NTP servers we achieve within 10ms generally.<br>> ><br>> > On Mon, Feb 17, 2020 at 4:09 PM Alex Balashov <abalashov@evaristesys.com> wrote:<br>> > ><br>> > > On Mon, Feb 17, 2020 at 04:00:25PM -0600, Hunter Fuller wrote:<br>> > ><br>> > > > On Mon, Feb 17, 2020 at 3:57 PM Mike Hammett <voiceops@ics-il.net><br>> > > > wrote:<br>> > > > > Is having four VMs running NTP a ridiculous proposition (well, other<br>> > > > > than resources, which it'll consume very little)?<br>> > > ><br>> > > > Yes. NTP servers should never run in VMs.<br>> > ><br>> > > I don't know about that. The nature of virtualisation has changed<br>> > > greatly over the past decade; VMs have gone from being a kludgy and slow<br>> > > software-emulated environment to almost a first-class CPU guest, thanks<br>> > > to paravirtualisation and supporting CPU features.<br>> > ><br>> > > And NTP is specifically designed for latency in a rather general sense.<br>> > ><br>> > > If you're using NTP for any really precise timing calibration, that's<br>> > > the wrong vehicle, anyway.<br>> > ><br>> > > -- Alex<br>> > ><br>> > > --<br>> > > Alex Balashov | Principal | Evariste Systems LLC<br>> > ><br>> > > Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)<br>> > > Web: http://www.evaristesys.com/, http://www.csrpswitch.com/<br>> > > _______________________________________________<br>> > > VoiceOps mailing list<br>> > > VoiceOps@voiceops.org<br>> > > https://puck.nether.net/mailman/listinfo/voiceops<br>><br>> --<br>> Alex Balashov | Principal | Evariste Systems LLC<br>><br>> Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)<br>> Web: http://www.evaristesys.com/, http://www.csrpswitch.com/<br>> _______________________________________________<br>> VoiceOps mailing list<br>> VoiceOps@voiceops.org<br>> https://puck.nether.net/mailman/listinfo/voiceops<br>_______________________________________________<br>VoiceOps mailing list<br>VoiceOps@voiceops.org<br>https://puck.nether.net/mailman/listinfo/voiceops<br></div><br></div></div></body></html>