nanog mailing list archives
Re: REMINDER: LEAP SECOND
From: Harlan Stenn <stenn () ntp org>
Date: Wed, 24 Jun 2015 00:37:51 +0000
shawn wilson writes:
On Jun 23, 2015 6:26 AM, "Nick Hilliard" <nick () foobar org> wrote:Blocking NTP at the NTP edge will probably work fine for most situations. Bear in mind that your NTP edge is not necessarily the same as yournetworkedge. E.g. you might have internal GPS / radio sources which could unexpectedly inject the leap second. The larger the network, the more likely this is to happen. Most organisations have network fossils and ntp is an excellent source of these. I.e. systems which work away for years without any problems before one day accidentally triggering meltdown because some developer didn't understand the subtleties of clockmonotonicity.NTP causes jumps - not skews, right?
Left to its default condition, ntp will step/jump a change in excess of 128msec. If you want to slew the clock instead, a 1 second correction will take a little over 33 minutes' time to apply. I don't understand why people believe that stopping ntpd for a few minutes while the leap second is applied will help. If the system clock keeps good time, it will *still* be about 1 second ahead when ntpd is restarted, and that will trigger a backward step which is fatal to a number of applications. H
Current thread:
- Re: REMINDER: LEAP SECOND, (continued)
- Re: REMINDER: LEAP SECOND Harlan Stenn (Jun 20)
- Re: REMINDER: LEAP SECOND Doug Barton (Jun 22)
- Re: REMINDER: LEAP SECOND Harlan Stenn (Jun 22)
- Re: REMINDER: LEAP SECOND Mel Beckman (Jun 23)
- Re: REMINDER: LEAP SECOND Harlan Stenn (Jun 23)
- Re: REMINDER: LEAP SECOND Mel Beckman (Jun 23)
- Re: REMINDER: LEAP SECOND Nick Hilliard (Jun 23)
- Re: REMINDER: LEAP SECOND shawn wilson (Jun 23)
- Re: REMINDER: LEAP SECOND Jared Mauch (Jun 23)
- Re: REMINDER: LEAP SECOND Nick Hilliard (Jun 23)
- Re: REMINDER: LEAP SECOND Harlan Stenn (Jun 23)
- Re: REMINDER: LEAP SECOND Matthew Huff (Jun 23)
- Re: REMINDER: LEAP SECOND Harlan Stenn (Jun 23)
- Re: REMINDER: LEAP SECOND Tore Anderson (Jun 23)
- Re: REMINDER: LEAP SECOND Philip Homburg (Jun 24)
- Re: REMINDER: LEAP SECOND Tony Finch (Jun 24)
- Re: REMINDER: LEAP SECOND Philip Homburg (Jun 24)
- Re: REMINDER: LEAP SECOND Majdi S. Abbas (Jun 24)
- Re: REMINDER: LEAP SECOND Chris Adams (Jun 24)
- Re: REMINDER: LEAP SECOND Tore Anderson (Jun 24)
- Re: REMINDER: LEAP SECOND Matthew Huff (Jun 24)