[time-nuts] Recommendations for NTP server

Geoff Powell geoff at g8kbz.demon.co.uk
Mon Apr 24 18:05:13 EDT 2006

In article <15153.1145871481 at critter.freebsd.dk>, Poul-Henning Kamp
<phk at phk.freebsd.dk> writes
>In message <Gb7QUsAye$SEFwKA at g8kbz.demon.co.uk>, Geoff Powell writes:
>>So you'd recommend a 4501, with FreeBSD in Compact Flash? I wanted to
>>use CF anyway, since a box running 24/7 is not the best environment in
>>which to have moving parts. The box will have no more that NTP and MRTG
>>on it.
>There isn't much I can add here, but I just want to add a few things:
>Sub-microsecond precision is impossible with regular crystals, end
>of story.  You need OCXO or Rb support for that.

Fine - I presume something like your web page about Soekris boards
(where you characterised the performance of such a unit at ultimate
precision) is the route to follow. I have follow-up plans for something
similar further down the road. This year, next year, sometime, never...

Meanwhile, FreeBSD with your patches on a NET4501 will give units of

>If you don't need the SNMP capability, drop MRTG and use RRDtool,
>(MRTG's more general sibling).

Rats! Another app to learn! But you're right, SNTP is a gong - the bells
and whistles I want are NTP stats.

>If you want to run MRTG or RRDtool, you probably do not want to use
>a CF card: it will wear out - eventually.  Don't trust more than a

Yes, I am aware of flash memory wear-out problems. I was thinking of
NFS-mounting a directory elsewhere on my network as scratch space.

>I wrote a hack called "Remote RRD" which sends updates in UDP packets
>to another host which hosts the RRD file and web-pages and all that
>to get around this problem.

Aha! A cure. Would you post a URL? Pretty please?

>Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
>phk at FreeBSD.ORG         | TCP/IP since RFC 956
>FreeBSD committer       | BSD since 4.3-tahoe    
>Never attribute to malice what can adequately be explained by incompetence.
>time-nuts mailing list
>time-nuts at febo.com

Geoff Powell

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