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 <[email protected]> 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 <[email protected]> > > 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 <[email protected]> > > > > 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/ > > > _______________________________________________ > > > 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 _______________________________________________ VoiceOps mailing list [email protected] https://puck.nether.net/mailman/listinfo/voiceops
