Ardi (Peter?),
wow, the way you are quoting makes it *really* hard to read your posts,
so this can just prevent folks here on the list from replying.
ardi wrote:
ardi wrote:
having 2 GPS sources and 4 peers to each other (see below the setup),
When turning on 5th and 6th peers, they disturb my setup.
[email protected]:~# ntpq -pn
remote refid st t when poll reach delay offset jitter
==============================================================================
*local.xx .GPS. 1 u 1 16 377 0.344 -0.037 0.046
+remote.yy .GPS. 1 u - 16 377 34.258 -0.074 0.273
-local.a1 xx.xx.xx.a1 2 u 12 16 377 0.286 0.043 0.015
+remote.b1 yy.yy.yy.b1 2 u 3 16 377 33.555 -0.016 0.055
-remote.b2 yy.yy.yy.b2 2 u 7 16 377 33.700 0.049 0.281
+local-annoying.c1 yy.yy.yy.c1 2 u 12 16 377 0.216 0.043 0.044
<--why? how to get rid of it?
+local-annoying.c2 yy.yy.yy.c2 2 u 12 16 377 0.326 0.043 0.03
<--why? how to get rid of it?
I'm missing why you find those two indicated so disturbing,
They both have lower latency than remote.yy, remote.b1, remote.b2
They both have lower jitter than remote.yy and remote.b2
Their offset is in line with local.a1, and less than remote.b2 and remote.yy
Ardi:
===ardi_start
let's skip this part - i can come back to this later.
===ardi_end
Is it possible to restrict to those 4 peers only
If you really don't want them, just comment them out in your conf?
Ardi:
===ardi_start
it is not question of commenting them - i can do it easily.
imagine a hypothetical situation, when somebody defines on network these extra 2 servers
on purpose to "inflict" the existing setup.
I would like to avoid it by correct setup on those 2 GPS sources and 4 peers.
If I understand this correctly then "local.xx" and "remote.yy" are not
GPS sources in the sense that the NTP daemon gets the time directly from
a GPS hardware refclock. Instead this looks like the client just polls 2
NTP servers claiming to be synchronized to GPS, one of them on the local
network and the other one at a remote site.
what i would like to achieve is that 4 peers getting time only from GPS sources
and from each other and all stratum3 servers and below can have the possibility
to get time only from any of those 4 peers.
If it's correct what I wrote above then at least the remote "GPS" source
provides much more jitter than the "local-annoying" time sources, so it
wouldn't be even surprising if ntpd preferred the "local-annoying" time
sources over the "remote.yy" GPS source.
Have you had a look at:
http://doc.ntp.org/4.2.6p5/prefer.html#peer
This explains the way ntpd selects the time sources it uses preferably.
[...]
===ardi_start
preferring a server is already included:
server xx.xx.xx.a2 minpoll 4 maxpoll 4 prefer
server xx.xx.xx.a1
Also see the link above to understand why "prefer" may not always work
as you might expect.
===ardi_end
xx.xx.xx.a2 .INIT. 16 u - 16 0 0.000 0.000 0.000 <---------does not get time
from xx.xx.xx.a2!!!!
(Shrug), looks like it is not getting packets back from a2.
If you get and decode the association information,
you might find out more; e.g.
ntpq -crv -clpe -clas -c "rv &1" (or whichever association index number is
relevant)
Ardi:
===ardi_start
this is the output on xx.xx.xx.t1 (stratum3)
xx.xx.xx.t1 # ntpq -crv -clpe -clas -c "rv &1"
associd=0 status=0615 leap_none, sync_ntp, 1 event, clock_sync,
version="ntpd [email protected] Sun Oct 17 13:35:13 UTC 2010 (1)",
processor="x86_64", system="Linux/2.6.32-5-amd64", leap=00, stratum=3,
precision=-22, rootdelay=3.731, rootdisp=45.673, refid=xx.xx.xx.a1,
reftime=d7fdc99c.3e3638ca Fri, Oct 31 2014 9:41:00.243,
clock=d7fdcbbd.e46ee56a Fri, Oct 31 2014 9:50:05.892, peer=64477,
tc=10, mintc=3, offset=1.619, frequency=5.247, sys_jitter=1.649,
clk_jitter=1.024, clk_wander=0.071
remote refid st t when poll reach delay offset jitter
==============================================================================
xx.xx.xx.a2 .INIT. 16 u - 16 0 0.000 0.000 0.000
*xx.xx.xx.a1 xx.xx.xx.xx 2 u 545 1024 377 3.243 1.619 1.649
ind assid status conf reach auth condition last_event cnt
===========================================================
1 64476 8011 yes no none reject mobilize 1
2 64477 963a yes yes none sys.peer sys_peer 3
associd=64476 status=8011 conf, sel_reject, 1 event, mobilize,
srcadr=xx.xx.xx.a2, srcport=123, dstadr=xx.xx.xx.t1,
dstport=123, leap=11, stratum=16, precision=-22, rootdelay=0.000,
rootdisp=0.000, refid=INIT,
reftime=00000000.00000000 Mon, Jan 1 1900 1:00:00.000,
rec=00000000.00000000 Mon, Jan 1 1900 1:00:00.000, reach=000,
unreach=9616, hmode=3, pmode=0, hpoll=4, ppoll=4, headway=2,
flash=1600 peer_stratum, peer_dist, peer_unreach, keyid=0, offset=0.000,
delay=0.000, dispersion=15937.500, jitter=0.000, xleave=0.020,
filtdelay= 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00,
filtoffset= 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00,
filtdisp= 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0
xx.xx.xx.t1 #
it can be seen that it does not accept time from xx.xx.xx.a2
This sounds like the upstream server isn't reachable, or claims to be
*not* synchronized.
why should i need to define peer in its config?
===ardi_end
{My wild guess would be lack of trust by t1
perhaps missing or mismatched keys.}
Ardi:
===ardi_start
why should i need keys toward stratum3? in case a-case used, it works
without keys ...
You have to take care when using the word "peer".
From the role in an NTP mesh 2 peers ( configured with "peer a.b.c.d")
are NTP servers which can affect the time of each other. In this case
the configured peers should use authentication to prevent other NTP
nodes from messing up the system time of the peering NTP servers.
In the output of a normal NTP client the configured servers are also
referred to as "peers", for example the "system peer" is labelled with a
'*' in the output of "ntpq -p", even though this can be an upstream NTP
server to which the client sends client request, or a peer to which the
machine sends active or passive peer packets, or a hardware refclock
directly connected to the local machine.
Martin
--
Martin Burnicki
Meinberg Funkuhren
Bad Pyrmont
Germany
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