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diff --git a/zarb-ml/mageia-dev/2013-February/022739.html b/zarb-ml/mageia-dev/2013-February/022739.html new file mode 100644 index 000000000..a48eb270a --- /dev/null +++ b/zarb-ml/mageia-dev/2013-February/022739.html @@ -0,0 +1,169 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML> + <HEAD> + <TITLE> [Mageia-dev] Why ntpdate still there? + </TITLE> + <LINK REL="Index" HREF="index.html" > + <LINK REL="made" HREF="mailto:mageia-dev%40mageia.org?Subject=Re%3A%20%5BMageia-dev%5D%20Why%20ntpdate%20still%20there%3F&In-Reply-To=%3C5118E18F.4070408%40colin.guthr.ie%3E"> + <META NAME="robots" CONTENT="index,nofollow"> + <META http-equiv="Content-Type" content="text/html; charset=us-ascii"> + <LINK REL="Previous" HREF="022737.html"> + <LINK REL="Next" HREF="022746.html"> + </HEAD> + <BODY BGCOLOR="#ffffff"> + <H1>[Mageia-dev] Why ntpdate still there?</H1> + <B>Colin Guthrie</B> + <A HREF="mailto:mageia-dev%40mageia.org?Subject=Re%3A%20%5BMageia-dev%5D%20Why%20ntpdate%20still%20there%3F&In-Reply-To=%3C5118E18F.4070408%40colin.guthr.ie%3E" + TITLE="[Mageia-dev] Why ntpdate still there?">mageia at colin.guthr.ie + </A><BR> + <I>Mon Feb 11 13:18:23 CET 2013</I> + <P><UL> + <LI>Previous message: <A HREF="022737.html">[Mageia-dev] Why ntpdate still there? +</A></li> + <LI>Next message: <A HREF="022746.html">[Mageia-dev] Why ntpdate still there? +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#22739">[ date ]</a> + <a href="thread.html#22739">[ thread ]</a> + <a href="subject.html#22739">[ subject ]</a> + <a href="author.html#22739">[ author ]</a> + </LI> + </UL> + <HR> +<!--beginarticle--> +<PRE>'Twas brillig, and Pierre Jarillon at 11/02/13 11:19 did gyre and gimble: +><i> ntpdate is no longer necessary because ntpd includes all functions necessary +</I>><i> to set the clock. +</I>><i> +</I>><i> Use of ntpdate in crontab is a very bad idea because a great number of users +</I>><i> can make a burst of activity and a saturation of servers. +</I>><i> ntpd is more accurate with few requests and can also setup the clock. +</I>><i> ntpd makes requests after a long time. More the clock is adjusted, more it +</I>><i> waits before a new request. +</I>><i> +</I>><i> +</I>><i> In man ntpdate, we can see: +</I>><i> Disclaimer: The functionality of this program is now available in the ntpd +</I>><i> program. See the -q command line option in the ntpd - Network Time Protocol +</I>><i> (NTP) daemon page. After a suitable period of mourning, the ntpdate program +</I>><i> is to be retired from this distribution. +</I>><i> +</I>><i> ntpdate and ntp are active in drakxservices... IMO, this is a nonsense. +</I> +ntpdate is a service that is run prior to ntpd itself. This was done +previously to ensure the time was set correctly due to a (deliberate) +limitation in ntpd itself which did not change the clock when large +jumps were involved. It attempts to keep the change continuous and +avoids large jumps. + +See this section from the man page: + + Under ordinary conditions, ntpd slews the clock so that the time +is effectively continuous and never runs backwards. If due to extreme +network congestion an error spike exceeds the + step threshold, by default 128 ms, the spike is discarded. +However, if the error persists for more than the stepout threshold, by +default 900 s, the system clock is stepped to the + correct value. In practice the need for a step has is extremely +rare and almost always the result of a hardware failure. With the -x +option the step threshold is increased to 600 s. + Other options are available using the tinker command on the +Miscellaneous Options page. + + The issues should be carefully considered before using these +options. The maximum slew rate possible is limited to 500 +parts-per-million (PPM) by the Unix kernel. As a result, the + clock can take 2000 s for each second the clock is outside the +acceptable range. During this interval the clock will not be consistent +with any other network clock and the system + cannot be used for distributed applications that require +correctly synchronized network time. + + +So ntpdate as a service is just a one-shot thing, it happens once at +boot to ensure the clocks are properly set and then ntpd takes over for +the rest of the time that machine stays up. + +As far as I'm aware, there is nothing integrated into crontab regarding +ntpdate, but please feel free to correct me on that one. + +Col + + + +-- + +Colin Guthrie +colin(at)mageia.org +<A HREF="http://colin.guthr.ie/">http://colin.guthr.ie/</A> + +Day Job: + Tribalogic Limited <A HREF="http://www.tribalogic.net/">http://www.tribalogic.net/</A> +Open Source: + Mageia Contributor <A HREF="http://www.mageia.org/">http://www.mageia.org/</A> + PulseAudio Hacker <A HREF="http://www.pulseaudio.org/">http://www.pulseaudio.org/</A> + Trac Hacker <A HREF="http://trac.edgewall.org/">http://trac.edgewall.org/</A> +</PRE> + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +<!--endarticle--> + <HR> + <P><UL> + <!--threads--> + <LI>Previous message: <A HREF="022737.html">[Mageia-dev] Why ntpdate still there? +</A></li> + <LI>Next message: <A HREF="022746.html">[Mageia-dev] Why ntpdate still there? +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#22739">[ date ]</a> + <a href="thread.html#22739">[ thread ]</a> + <a href="subject.html#22739">[ subject ]</a> + <a href="author.html#22739">[ author ]</a> + </LI> + </UL> + +<hr> +<a href="https://www.mageia.org/mailman/listinfo/mageia-dev">More information about the Mageia-dev +mailing list</a><br> +</body></html> |