Aw: Re: Re: [chrony-users] How to use Facebook's NTP-service correctly?
Miroslav wrote: > A leap-smearing server suppresses the leap second bits in its > responses, but it could happen if the client knew from other time > sources or tzdata (enabled by leapsectz) that there was a leap second. So before using a new NTP service, it's needed to do some research. Or does the NTP (rfc958) have some kind of identification, if it has leap smearing or what's the primary source? -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
Aw: Re: Re: Re: [chrony-users] How to use Facebook's NTP-service correctly?
William G. Unruh wrote: > Yes. That was why Miroslav said it should be the user machine's responsibility > to smear, not the server's. The server should deliver UTC, and UTC has leap > seconds > (ie 23:59:58 goes to 00:00:00 or 23:59:59 goes to 25:59:60 and then to > 00:00:00.) > AFAIK there is not standard signal to say "I am smearing the leap second" You > have to know. > Leap seconds are announced months in advance, and leap second files are > distributed, > and many machines use that to know when leap seconds occur. Okay, understood. So either: 1. Always use Facebook's time service only (when using it), never mix it with anything (the user needs to be aware of the server's signal configuration) 2. When using Facebook's time service with Chrony, anything is fine, smearing works, but Chrony-internal smearing should be deactivated (Chrony seems to automatically deactivate it, since there's no leap bit coming in). 3. When using Facebook's time service with anything else, smearing also works, since it's done on their server (but the user needs to be aware of this) 4. When using Chrony, any normal NTP service (which doesn't do server sided smearing) can be used and Chrony can do the smearing if configurated. Even if obvious to Chrony familar users, we should write that into the FAQ ;) -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
Aw: Re: [chrony-users] How to use Facebook's NTP-service correctly?
Hey Holger, Holger wrote: > an important point for you since you're presumably in Germany and Jawoll, under protection of CoronaSchVO NW. > I already went through the futile attempts to use these servers: > they're all outside Germany, with rather high latency and quite > terrible connectivity, depending on your ISP's routing and current > backbone load. According to their blog, they're doing geo-routing to the nearst server. Maybe it's for their own services only, not for the public one. > You're much better off using the public .de NTP pool or addressing > 1..3 public servers explicitly. I've set my router to pull from three > stable Stratum 1 sources and get excellent, always-available results > on all my inhouse clients, e.g. this on my workstation: > > $chronycmd sources > MS Name/IP address Stratum Poll Reach LastRx Last sample > === > ^* bifrost.applied-asynchro> 2 6 37725 -3937ns[-7799ns] +/- > 5388us > > $chronycmd sourcestats > Name/IP AddressNP NR Span Frequency Freq Skew Offset Std Dev > == > bifrost.applied-asynchro> 8 6 229 -0.002 0.164-46ns 7193ns Would you share your complete config as a good/best practice example? Best regards, Lars-Daniel -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
Aw: Re: Re: [chrony-users] How to use Facebook's NTP-service correctly?
Miroslav wrote: > On Wed, Apr 08, 2020 at 02:16:23PM +0200, Lars-Daniel Weber wrote: > > > On the manfile to chrony.conf there's also this as a recommendation: > > > leapsecmode slew > > > maxslewrate 1000 > > > smoothtime 400 0.001 leaponly > > That's what Facebook did on their servers. On a client it either won't > make a difference or it will cause the client to start a (wrong) slew > at the midnight and it will take some time to recover from it. So for logging on a webserver (with database and stuff), you'd recommend to use Holger's settings? -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
Aw: Re: [chrony-users] How to use Facebook's NTP-service correctly?
Holger wrote: > It's really just a cleaned up default (template) config.. On the manfile to chrony.conf there's also this as a recommendation: > leapsecmode slew > maxslewrate 1000 > smoothtime 400 0.001 leaponly https://chrony.tuxfamily.org/doc/3.4/chrony.conf.html I'll give it a try. -- To unsubscribe email chrony-users-requ...@chrony.tuxfamily.org with "unsubscribe" in the subject. For help email chrony-users-requ...@chrony.tuxfamily.org with "help" in the subject. Trouble? Email listmas...@chrony.tuxfamily.org.
