On (2014-02-08 19:43 -0500), Jay Ashworth wrote:
> In the architecture I described, though, is it really true that the odds
> of the common types of failure are higher than with only one?
I think so, lets assume arbitrarily that probability of NTP server not
starting to give incorrect time is 99%
Best practice is five. =) I don't remember if it's in FAQ on ntp.org or in
David Mills' book. Your local clock is kind of gullible "push-over" which
will "vote" for the "party" providing most reasonable data. The algorithm
would filter out insane sources which run too far from the rest and then
gro
- Original Message -
> From: "Saku Ytti"
> > In the architecture I described, though, is it really true that the
> > odds of the common types of failure are higher than with only one?
>
> I think so, lets assume arbitrarily that probability of NTP server not
> starting to give incorrect
On (2014-02-09 15:16 -0500), Jay Ashworth wrote:
> > Then either of two servers not giving incorrect time is 0.99**2 i.e. 98%, so
> > two NTP servers would be 1% point more likely to give incorrect time than
> > one
> > over 1 year time.
>
> That's only true if the two devices have common failur
- Original Message -
> From: "Saku Ytti"
> > That's only true if the two devices have common failure modes,
> > though, is it not?
>
> No, we can assume arbitrary fault which causes NTP to output bad time. With
> two NTP servers it's more likely that any one of them will start doing
> th
On 2/9/2014 2:45 PM, Jay Ashworth wrote:
Or do I understand NTP less well than I think?
I am of the private opinion that if your name is not "David Mill" (and
MAYBE if it IS) the answer is either "42" or "yes".
--
Requiescas in pace o email Two identifying characteristics
On (2014-02-09 15:45 -0500), Jay Ashworth wrote:
> If I'm locked to 2 coherent upstreams and one goes insane, I'm going to
> know which one it is, because the other one will still match what I already
> have running, no?
>
> Or do I understand NTP less well than I think?
I don't think you can re
On Sun, Feb 9, 2014 at 2:45 PM, Jay Ashworth wrote:
[snip]
> If I'm locked to 2 coherent upstreams and one goes insane, I'm going to
> know which one it is, because the other one will still match what I already
> have running, no?
The question should be how assured is the reliability of the clo
On (2014-02-09 21:08 +0100), Andriy Bilous wrote:
> Best practice is five. =) I don't remember if it's in FAQ on ntp.org or in
> David Mills' book. Your local clock is kind of gullible "push-over" which
> will "vote" for the "party" providing most reasonable data. The algorithm
> would filter out
Look back in the archives and see the problems that erupted when one of
the big guys rebooted and came on line with bad time(tock.usno.navy.mil
in Nov of 2012). It was talked about in Outages and other lists at the
time it happened.
On 02/09/14 14:56, Saku Ytti wrote:
On (2014-02-09 15:45 -
On Sun, Feb 09, 2014 at 03:45:19PM -0500, Jay Ashworth wrote:
> - Original Message -
> > From: "Saku Ytti"
>
> > > That's only true if the two devices have common failure modes,
> > > though, is it not?
> >
> > No, we can assume arbitrary fault which causes NTP to output bad time. With
>
Unfortunately I don't have the book handy. May be I am wrong too. Just
checked and 4 looks to be a valid solution for 1 falseticker according to
Byzantine Generals' Problem.
On Sun, Feb 9, 2014 at 10:03 PM, Saku Ytti wrote:
> On (2014-02-09 21:08 +0100), Andriy Bilous wrote:
>
> > Best practice
On Feb 9, 2014, at 3:50 PM, Larry Sheldon wrote:
> On 2/9/2014 2:45 PM, Jay Ashworth wrote:
>
>> Or do I understand NTP less well than I think?
>
> I am of the private opinion that if your name is not "David Mill" (and MAYBE
> if it IS) the answer is either "42" or "yes".
> — ...
From http://
On 2/9/2014 6:42 PM, James R Cutler wrote:
On Feb 9, 2014, at 3:50 PM, Larry Sheldon
wrote:
On 2/9/2014 2:45 PM, Jay Ashworth wrote:
Or do I understand NTP less well than I think?
I am of the private opinion that if your name is not "David Mill"
(and MAYBE if it IS) the answer is either "4
On 2/9/2014 7:04 PM, Larry Sheldon wrote:
In the 1990s I found myself administering a campus network for a
University--the only people less prepared than I as everybody else.
In the 1990s I found myself administering a campus network for a
University--the only people less prepared than I Was ev
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