[ntp:questions] ntpd stuck at default minpoll on stratum one
Hi, I have a stratum one server running ntpd [EMAIL PROTECTED] with a Garmin GPS 18 LVC as a refclock. I use the shmpps driver from http://time.qnan.org/ . Since this driver only provides the PPS signal, I need to have a few other servers defined in my ntp.conf so that my ntpd knows what time it is. Here's my concern: the poll interval on those servers is always stuck at the default minpoll (64sec), even though I have not specified so. I would rather not poll those servers at such a rapid rate, but ntpd seems to be doing this on its own, as far as I know. It's been this way since I set up the server, about two months ago. I haven't messed with it, as I assume ntpd knows what it's doing. However, my concern has finally prompted me to ask someone. Here is my ntp.conf (comments removed): restrict default kod nopeer nomodify notrap restrict 127.0.0.1 server 127.127.28.0 minpoll 4 maxpoll 4 prefer fudge 127.127.28.0 refid PPS flag3 1 server tick.ucla.edu iburst server clock.via.net iburst server t1.timegps.net iburst server bigben.cac.washington.edu iburst server clepsydra.dec.com iburst driftfile /var/lib/ntp.drift logfile /var/log/ntp/ntp.log statsdir /var/log/ntp/ statistics loopstats peerstats clockstats filegen loopstats file loopstats type day enable filegen peerstats file peerstats type day enable filegen clockstats file clockstats type day enable keys /etc/ntp/keys trustedkey 1 requestkey 1 controlkey 1 And here is a 'ntpq -p' and 'ntpq -crv' output: saturn:# ntpq -p remote refid st t when poll reach delay offset jitter = *SHM(0) .PPS. 0 l 14 16 3770.0000.000 0.001 -tick.ucla.edu .GPS. 1 u 37 64 377 38.9102.332 1.286 -clock.via.net .GPS. 1 u 51 64 377 34.7222.470 3.509 +cpe-76-87-109-2 .GPS. 1 u 44 64 377 53.4600.611 5.654 -bigben.cac.wash .USNO. 1 u 36 64 377 13.5902.795 2.597 +clepsydra.dec.c .GPS. 1 u 29 64 377 30.1611.618 1.432 saturn:# ntpq -crv assID=0 status=0964 leap_none, sync_telephone, 6 events, event_peer/strat_chg, version="ntpd [EMAIL PROTECTED] Wed Aug 22 18:27:01 UTC 2007 (1)", processor="i686", system="Linux/2.6.17-5mdv", leap=00, stratum=1, precision=-20, rootdelay=0.000, rootdispersion=0.343, peer=22004, refid=PPS, reftime=cab1a338.1c12986c Fri, Oct 5 2007 23:01:28.109, poll=4, clock=cab1a33e.4d9c88ab Fri, Oct 5 2007 23:01:34.303, state=4, offset=0.000, frequency=-22.221, jitter=0.001, noise=0.001, stability=0.000 Thanks for any help. Regards, -- Dennis Hilberg, Jr. timekeeper(at)dennishilberg(dot)com NTP Server Information: http://saturn.dennishilberg.com/ntp.php ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpd stuck at default minpoll on stratum one
Dennis Hilberg, Jr. wrote: > Hi, > > I have a stratum one server running ntpd [EMAIL PROTECTED] with a Garmin > GPS 18 LVC as a refclock. I use the shmpps driver from > http://time.qnan.org/ . Since this driver only provides the PPS signal, > I need to have a few other servers defined in my ntp.conf so that my > ntpd knows what time it is. > > Here's my concern: the poll interval on those servers is always stuck at > the default minpoll (64sec), even though I have not specified so. I > would rather not poll those servers at such a rapid rate, but ntpd seems > to be doing this on its own, as far as I know. I think this is a known problem/bug/feature: The prefer peer responsible for naming the PPS ticks is clamped at minpoll. In fact, if you adjust minpoll to 4 (i.e. 16 seconds), which can be a good idea for a GPS-class PPS signal, then you'll also lock your prefer peer at the same rate. One possible workaround is to set your prefer peer to another local/personal server which uses the Internet to get its timestamps. Terje -- - <[EMAIL PROTECTED]> "almost all programming can be viewed as an exercise in caching" ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpd stuck at default minpoll on stratum one
In article <[EMAIL PROTECTED]> Terje Mathisen <[EMAIL PROTECTED]> writes: >Dennis Hilberg, Jr. wrote: >> Hi, >> >> I have a stratum one server running ntpd [EMAIL PROTECTED] with a Garmin >> GPS 18 LVC as a refclock. I use the shmpps driver from >> http://time.qnan.org/ . Since this driver only provides the PPS signal, >> I need to have a few other servers defined in my ntp.conf so that my >> ntpd knows what time it is. >> >> Here's my concern: the poll interval on those servers is always stuck at >> the default minpoll (64sec), even though I have not specified so. I >> would rather not poll those servers at such a rapid rate, but ntpd seems >> to be doing this on its own, as far as I know. > >I think this is a known problem/bug/feature: The prefer peer responsible >for naming the PPS ticks is clamped at minpoll. In fact, if you adjust >minpoll to 4 (i.e. 16 seconds), which can be a good idea for a GPS-class >PPS signal, then you'll also lock your prefer peer at the same rate. AFAIK it's not limited to the prefer peer - note that Dennis' ntp.conf didn't have 'prefer' on *any* of the remote servers, I believe having one used to be a requirement for a PPS-only clock to work, but apparently that has changed. I.e. if you have a reference clock, *all* remote servers will be clamped at minpoll for the reference clock. --Per Hedeland [EMAIL PROTECTED] ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpd stuck at default minpoll on stratum one
Guys, There's a small matter of physics here. The PPS driver clamps the poll interval and time constant to minpoll, since that's consistent with the nominal Allan intercept and gives the best overall performance. The general rule is that the server poll interval must not be greater than the time constant in order that the feedback loop is never undersampled, even under conditions of clockhop from one source to another. Otherwise, should the PPS signal fail and the prefer peer take over poll interval much higher, the loop can become unstable. Usually, the PPS is used in conjunction with a local reference clock, so this is not an issue. It is in principle possible to poll the outside server at a longer interval, but the complexities of this and the clockhop issue don't seem to be worth the hazards. Dave Per Hedeland wrote: > In article <[EMAIL PROTECTED]> Terje Mathisen > <[EMAIL PROTECTED]> writes: > >>Dennis Hilberg, Jr. wrote: >> >>>Hi, >>> >>>I have a stratum one server running ntpd [EMAIL PROTECTED] with a Garmin >>>GPS 18 LVC as a refclock. I use the shmpps driver from >>>http://time.qnan.org/ . Since this driver only provides the PPS signal, >>>I need to have a few other servers defined in my ntp.conf so that my >>>ntpd knows what time it is. >>> >>>Here's my concern: the poll interval on those servers is always stuck at >>>the default minpoll (64sec), even though I have not specified so. I >>>would rather not poll those servers at such a rapid rate, but ntpd seems >>>to be doing this on its own, as far as I know. >> >>I think this is a known problem/bug/feature: The prefer peer responsible >>for naming the PPS ticks is clamped at minpoll. In fact, if you adjust >>minpoll to 4 (i.e. 16 seconds), which can be a good idea for a GPS-class >>PPS signal, then you'll also lock your prefer peer at the same rate. > > > AFAIK it's not limited to the prefer peer - note that Dennis' ntp.conf > didn't have 'prefer' on *any* of the remote servers, I believe having > one used to be a requirement for a PPS-only clock to work, but > apparently that has changed. I.e. if you have a reference clock, *all* > remote servers will be clamped at minpoll for the reference clock. > > --Per Hedeland > [EMAIL PROTECTED] ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
[ntp:questions] ntpd just not working
Hi, For some reason ntpd never seems to work for me. It looks like it is but once in a while I start getting "clock skew too great" kerberos errors. I can stop ntpd and do an ntpdate to sync up and I'm ok again for a while. Here's all my info: 18899 ?SLs0:00 ntpd -u ntp:ntp -p /var/run/ntpd.pid -g # cat ntp.conf restrict default ignore restrict 127.0.0.1 server 192.168.2.15 restrict 192.168.2.15 mask 255.255.255.255 nomodify notrap noquery driftfile /var/lib/ntp/drift # rpm -qa | grep ntp ntp-4.2.2p1-5.el5 # cat /etc/redhat-release CentOS release 5 (Final) # /etc/init.d/ntpd stop Shutting down ntpd:[ OK ] # ntpdate 192.168.2.15 6 Oct 17:49:29 ntpdate[18940]: step time server 192.168.2.15 offset -304.547963 sec Could it be that the ntpd that ships with CentOS is just crappy? Where can I find a good ntp daemon that works? Or is it because the machine is a cheapo AMD 64 thing I got from Circuit City? I should also mention that I'm running VMWare Server on the host. I would suspect it was responsible but changing the time in VMs reverts to the host time so I think that's good evidence that the host is authoritative. I have also have kernel params 'acpi=off clock=pmtmr' (a previous effort to fix this problem). Another thing that may or may not be related is that occasionally, if I leave an SSH session inactive for a few minutes, it becomes completely unresponsive for 30 seconds. Then it suddenly starts working normally again. Any ideas? Mike ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpd just not working
"Michael B Allen" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > For some reason ntpd never seems to work for me. It looks like it is > but once in a while I start getting "clock skew too great" kerberos > errors. I can stop ntpd and do an ntpdate to sync up and I'm ok again > for a while. > > Here's all my info: Not all, in fact. The first thing to look at is 'ntpq -p'. Did you review your firewall? > 18899 ?SLs0:00 ntpd -u ntp:ntp -p /var/run/ntpd.pid -g > > # cat ntp.conf > restrict default ignore > restrict 127.0.0.1 > server 192.168.2.15 > restrict 192.168.2.15 mask 255.255.255.255 nomodify notrap noquery > driftfile /var/lib/ntp/drift I'd be very wary of the restrictions. They look okay, but you might try going without them for a bit. Is 192.168.2.15 a good server? Where does it get its time? What reach does it have in the ntpq output? [...] > Could it be that the ntpd that ships with CentOS is just crappy? Where > can I find a good ntp daemon that works? Hardly. > Or is it because the machine is a cheapo AMD 64 thing I got from > Circuit City? Hardly. > I should also mention that I'm running VMWare Server on the host. I > would suspect it was responsible but changing the time in VMs reverts > to the host time so I think that's good evidence that the host is > authoritative. Run NTP on the host. Enable VMware's time sync option in the VMs. > I have also have kernel params 'acpi=off clock=pmtmr' (a previous > effort to fix this problem). Shouldn't matter. Might as well take them out, they probably do more harm than good. > Another thing that may or may not be related is that occasionally, if I > leave an SSH session inactive for a few minutes, it becomes completely > unresponsive for 30 seconds. Then it suddenly starts working normally > again. It may be related. The description is not enough to diagnose the problem. Groetjes, Maarten Wiltink ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpd just not working
On Sun, 7 Oct 2007 00:15:54 +0200 "Maarten Wiltink" <[EMAIL PROTECTED]> wrote: > "Michael B Allen" <[EMAIL PROTECTED]> wrote in message > news:[EMAIL PROTECTED] > > > For some reason ntpd never seems to work for me. It looks like it is > > but once in a while I start getting "clock skew too great" kerberos > > errors. I can stop ntpd and do an ntpdate to sync up and I'm ok again > > for a while. > > > > Here's all my info: > > Not all, in fact. The first thing to look at is 'ntpq -p'. Hey Maarten, # ntpq -p s0.foo.net: timed out, nothing received ***Request timed out No response. I reduced the ntp.conf to: # cat ntp.conf server 192.168.2.15 driftfile /var/lib/ntp/drift and get a response now but of course I don't know what association IDs are or if I need them: # ntpq -p No association ID's returned # ntpq -p 192.168.2.15 remote refid st t when poll reach delay offset jitter == *felix.headdown. 62.119.40.98 2 u 807 1024 377 120.0660.864 0.670 +petrel.telecom. 192.36.143.150 2 u 737 1024 377 142.0542.234 0.414 +ohno.mrbill.net 192.43.244.182 u 708 1024 377 60.775 -1.755 0.129 LOCAL(0)LOCAL(0)10 l4 64 3770.0000.000 0.004 > Did you review your firewall? No firewalls. It's an IntrAnet. Mike ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] ntpd just not working
On Sat, 6 Oct 2007 21:46:35 -0400 Michael B Allen <[EMAIL PROTECTED]> wrote: > # ntpq -p > No association ID's returned Incedentally, if I look the capture of this I see: Leap Indicator: alarm condition (clock not synchronized) (3) Mike ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
Re: [ntp:questions] pool.ntp.org large spikes?
On Wed, 12 Sep 2007 02:49:34 -0500, Hal Murray wrote: >>AFAIK all attempts to contact Turk Telecom have failed so far, I myself >>sent a mail to their Technical Director but never got any response. > > It's nothing personal. They have a similar reputation in the anti-spam > community for being short of clues and not talking to anybody about it. > > It might take something like blocking all their requests to the DNS > servers to attract their attention. I consider Hal too polite. All of Turk Telecom should be blocked at everyone's border router. -- 2007/10/07:03:16:55UTC Slackware Linux 2.4.32 up 46 days, 17:52, 6 users, load average: 2.15, 2.16, 2.10 ___ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
