Time synchronization of machines on LAN to GPS NTP server on the LAN
I have 4 computers on a LAN that need to have their system clocks closely synchronized within a ms or so if possible. I have just installed a GPS based time server (ESE-104A) on the LAN. At this point the LAN is connected to a router and the internet but the router will not be connected to the internet when operational.
In operation the whole system will be started when power is applied to the machines, NTP server, and router.
How can I set Ubuntu to sync every so many minutes and calculate what the period should be?
How can I get an idea of how long it takes to settle down and what the quality of the time keeping is?
I found a reference, from around 2000 perhaps, that suggests that the hwclock should be synched from the system time only at shut down. Should I do this and how?
What log files should I keep?
Here's the results of "ntpq -
remote refid st t when poll reach delay offset jitter
*nts .M-@M-(^AM-R. 1 u 29 128 377 38.912 -7.739 7.195
Here's my ntp.conf (I use IPv4 only)
driftfile /etc/ntp.drift
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
server 192.168.1.210
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery
restrict 127.0.0.1
restrict ::1
ntp
edited 2 hours ago
Rui F Ribeiro
41.5k1483140
asked Apr 20 '13 at 19:04
Nate LockwoodNate Lockwood
1489
add a comment |
I have 4 computers on a LAN that need to have their system clocks closely synchronized within a ms or so if possible. I have just installed a GPS based time server (ESE-104A) on the LAN. At this point the LAN is connected to a router and the internet but the router will not be connected to the internet when operational.
In operation the whole system will be started when power is applied to the machines, NTP server, and router.
How can I set Ubuntu to sync every so many minutes and calculate what the period should be?
How can I get an idea of how long it takes to settle down and what the quality of the time keeping is?
I found a reference, from around 2000 perhaps, that suggests that the hwclock should be synched from the system time only at shut down. Should I do this and how?
What log files should I keep?
Here's the results of "ntpq -
remote refid st t when poll reach delay offset jitter
*nts .M-@M-(^AM-R. 1 u 29 128 377 38.912 -7.739 7.195
Here's my ntp.conf (I use IPv4 only)
driftfile /etc/ntp.drift
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
server 192.168.1.210
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery
restrict 127.0.0.1
restrict ::1
ntp
edited 2 hours ago
Rui F Ribeiro
41.5k1483140
asked Apr 20 '13 at 19:04
Nate LockwoodNate Lockwood
1489
1
Welcome to SE, your question is very well thought out and asked, based on that there's no way you could be a SYSADMIN 8-).
– slm♦
Apr 20 '13 at 22:16
By saying I have a NTP server on the LAN I do not mean that it is a computer acting as a NTP server. It's an appliance that gets its time from GPS and makes it available to NTP requests through the NTP port.
– Nate Lockwood
Apr 21 '13 at 17:40
Thanks for the clarification. Given that I'd think either mine or Martin's answer would work OK for you. Probably would lean towards Martin's answer as the way to go if I was you.
– slm♦
Apr 21 '13 at 17:47
add a comment |
I have 4 computers on a LAN that need to have their system clocks closely synchronized within a ms or so if possible. I have just installed a GPS based time server (ESE-104A) on the LAN. At this point the LAN is connected to a router and the internet but the router will not be connected to the internet when operational.
In operation the whole system will be started when power is applied to the machines, NTP server, and router.
How can I set Ubuntu to sync every so many minutes and calculate what the period should be?
How can I get an idea of how long it takes to settle down and what the quality of the time keeping is?
I found a reference, from around 2000 perhaps, that suggests that the hwclock should be synched from the system time only at shut down. Should I do this and how?
What log files should I keep?
Here's the results of "ntpq -
remote refid st t when poll reach delay offset jitter
*nts .M-@M-(^AM-R. 1 u 29 128 377 38.912 -7.739 7.195
Here's my ntp.conf (I use IPv4 only)
driftfile /etc/ntp.drift
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
server 192.168.1.210
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery
restrict 127.0.0.1
restrict ::1
ntp
edited 2 hours ago
Rui F Ribeiro
41.5k1483140
asked Apr 20 '13 at 19:04
Nate LockwoodNate Lockwood
1489
I have 4 computers on a LAN that need to have their system clocks closely synchronized within a ms or so if possible. I have just installed a GPS based time server (ESE-104A) on the LAN. At this point the LAN is connected to a router and the internet but the router will not be connected to the internet when operational.
In operation the whole system will be started when power is applied to the machines, NTP server, and router.
How can I set Ubuntu to sync every so many minutes and calculate what the period should be?
How can I get an idea of how long it takes to settle down and what the quality of the time keeping is?
I found a reference, from around 2000 perhaps, that suggests that the hwclock should be synched from the system time only at shut down. Should I do this and how?
What log files should I keep?
Here's the results of "ntpq -
remote refid st t when poll reach delay offset jitter
*nts .M-@M-(^AM-R. 1 u 29 128 377 38.912 -7.739 7.195
Here's my ntp.conf (I use IPv4 only)
driftfile /etc/ntp.drift
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
server 192.168.1.210
restrict -4 default kod notrap nomodify nopeer noquery
restrict -6 default kod notrap nomodify nopeer noquery
restrict 127.0.0.1
restrict ::1
ntp
ntp
edited 2 hours ago
Rui F Ribeiro
41.5k1483140
asked Apr 20 '13 at 19:04
Nate LockwoodNate Lockwood
1489
edited 2 hours ago
Rui F Ribeiro
41.5k1483140
asked Apr 20 '13 at 19:04
Nate LockwoodNate Lockwood
1489
edited 2 hours ago
Rui F Ribeiro
41.5k1483140
edited 2 hours ago
Rui F Ribeiro
41.5k1483140
edited 2 hours ago
Rui F Ribeiro
41.5k1483140
41.5k1483140
asked Apr 20 '13 at 19:04
Nate LockwoodNate Lockwood
1489
asked Apr 20 '13 at 19:04
Nate LockwoodNate Lockwood
1489
asked Apr 20 '13 at 19:04
Nate LockwoodNate Lockwood
1489
1489
1
Welcome to SE, your question is very well thought out and asked, based on that there's no way you could be a SYSADMIN 8-).
– slm♦
Apr 20 '13 at 22:16
By saying I have a NTP server on the LAN I do not mean that it is a computer acting as a NTP server. It's an appliance that gets its time from GPS and makes it available to NTP requests through the NTP port.
– Nate Lockwood
Apr 21 '13 at 17:40
Thanks for the clarification. Given that I'd think either mine or Martin's answer would work OK for you. Probably would lean towards Martin's answer as the way to go if I was you.
– slm♦
Apr 21 '13 at 17:47
add a comment |
1
Welcome to SE, your question is very well thought out and asked, based on that there's no way you could be a SYSADMIN 8-).
– slm♦
Apr 20 '13 at 22:16
By saying I have a NTP server on the LAN I do not mean that it is a computer acting as a NTP server. It's an appliance that gets its time from GPS and makes it available to NTP requests through the NTP port.
– Nate Lockwood
Apr 21 '13 at 17:40
Thanks for the clarification. Given that I'd think either mine or Martin's answer would work OK for you. Probably would lean towards Martin's answer as the way to go if I was you.
– slm♦
Apr 21 '13 at 17:47
1
1
Welcome to SE, your question is very well thought out and asked, based on that there's no way you could be a SYSADMIN 8-).
– slm♦
Apr 20 '13 at 22:16
Welcome to SE, your question is very well thought out and asked, based on that there's no way you could be a SYSADMIN 8-).
– slm♦
Apr 20 '13 at 22:16
By saying I have a NTP server on the LAN I do not mean that it is a computer acting as a NTP server. It's an appliance that gets its time from GPS and makes it available to NTP requests through the NTP port.
– Nate Lockwood
Apr 21 '13 at 17:40
By saying I have a NTP server on the LAN I do not mean that it is a computer acting as a NTP server. It's an appliance that gets its time from GPS and makes it available to NTP requests through the NTP port.
– Nate Lockwood
Apr 21 '13 at 17:40
Thanks for the clarification. Given that I'd think either mine or Martin's answer would work OK for you. Probably would lean towards Martin's answer as the way to go if I was you.
– slm♦
Apr 21 '13 at 17:47
Thanks for the clarification. Given that I'd think either mine or Martin's answer would work OK for you. Probably would lean towards Martin's answer as the way to go if I was you.
– slm♦
Apr 21 '13 at 17:47
add a comment |
2 Answers
2
active
oldest
votes
Run ntpd on all machines. Set the server so that it gets its time from the gps receiver and point the other machines to the server. With iburst the clients will sync fast enough for your purposes.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 21 '13 at 13:10
Martin SchröderMartin Schröder
6451827
@sim I fell back to this solution but first I needed to disable apparmor in Ubuntu. It was restricting ntpd access to the drif file. Today the drift files appear to be up to date and the jitter is reasonable if not a bit higher that I'd like. Using tcpdump I see traffic on the LAN that I really don't understand but will work on that question later.
– Nate Lockwood
Apr 24 '13 at 17:46
add a comment |
I've usually setup systems so that as part of their power up routine that they'd initially run ntpdate and get their time bootstrapped from the local time server just so they aren't initially wildly off. Then just start up ntpd using it's default options.
For example, at the end of the file: /etc/rc.local add the following line:
/etc/init.d/ntpd stop
ntpdate <local time server>
/etc/init.d/ntpd start
It's hacky but does the job. I found this thread on Server fault that discusses reasons for not turning NTP into Frankenstein's monster by making it do something it was never meant to do, mainly keep precise time.
If you're really bent on getting precise time I think you'd be better off with this: Precise Time Protocol. There is an open source project that has implemented the PTP protocol, aptly named The Linux PTP Project.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 20 '13 at 23:24
slm♦slm
254k71536687
ntpdateis not needed;ntpdcan set the time at startup.
– Martin Schröder
Apr 21 '13 at 13:06
@Martin For about two minutes after start up the NTP appliance will not have a "lock" on a GPS satellite and will give its best estimate from its battery powered clock. Will I need to compensate for this?
– Nate Lockwood
Apr 21 '13 at 17:47
1
If you look at the iburst link that @Martin provided the first paragraph covers your question. ... "The iburst option does several checks quickly as soon as the daemon is started and whenever the server is unreachable if you have that in your configuration. The burst option does several checks quickly whenever the server is reachable."
– slm♦
Apr 21 '13 at 17:51
@MartinSchröder Between the two of you and a 10 year old Linux guide I'm starting to get a handle on this. Where, that is, what file starts ntpd on boot and is that the spot that ntpd is told how often to check the ntp server?
– Nate Lockwood
Apr 21 '13 at 20:59
@NateLockwood: ntpd checks the server as often as needed: You don't have to tell it the interval. Please read the FAQ. The startup of ntpd is handled by your OS - typically it should "just work".
– Martin Schröder
Apr 21 '13 at 21:45
add a comment |
Your Answer
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "106"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f73116%2ftime-synchronization-of-machines-on-lan-to-gps-ntp-server-on-the-lan%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
Run ntpd on all machines. Set the server so that it gets its time from the gps receiver and point the other machines to the server. With iburst the clients will sync fast enough for your purposes.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 21 '13 at 13:10
Martin SchröderMartin Schröder
6451827
@sim I fell back to this solution but first I needed to disable apparmor in Ubuntu. It was restricting ntpd access to the drif file. Today the drift files appear to be up to date and the jitter is reasonable if not a bit higher that I'd like. Using tcpdump I see traffic on the LAN that I really don't understand but will work on that question later.
– Nate Lockwood
Apr 24 '13 at 17:46
add a comment |
Run ntpd on all machines. Set the server so that it gets its time from the gps receiver and point the other machines to the server. With iburst the clients will sync fast enough for your purposes.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 21 '13 at 13:10
Martin SchröderMartin Schröder
6451827
@sim I fell back to this solution but first I needed to disable apparmor in Ubuntu. It was restricting ntpd access to the drif file. Today the drift files appear to be up to date and the jitter is reasonable if not a bit higher that I'd like. Using tcpdump I see traffic on the LAN that I really don't understand but will work on that question later.
– Nate Lockwood
Apr 24 '13 at 17:46
add a comment |
Run ntpd on all machines. Set the server so that it gets its time from the gps receiver and point the other machines to the server. With iburst the clients will sync fast enough for your purposes.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 21 '13 at 13:10
Martin SchröderMartin Schröder
6451827
Run ntpd on all machines. Set the server so that it gets its time from the gps receiver and point the other machines to the server. With iburst the clients will sync fast enough for your purposes.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 21 '13 at 13:10
Martin SchröderMartin Schröder
6451827
edited Apr 13 '17 at 12:13
Community♦
1
edited Apr 13 '17 at 12:13
Community♦
1
edited Apr 13 '17 at 12:13
Community♦
1
1
answered Apr 21 '13 at 13:10
Martin SchröderMartin Schröder
6451827
answered Apr 21 '13 at 13:10
Martin SchröderMartin Schröder
6451827
answered Apr 21 '13 at 13:10
Martin SchröderMartin Schröder
6451827
6451827
@sim I fell back to this solution but first I needed to disable apparmor in Ubuntu. It was restricting ntpd access to the drif file. Today the drift files appear to be up to date and the jitter is reasonable if not a bit higher that I'd like. Using tcpdump I see traffic on the LAN that I really don't understand but will work on that question later.
– Nate Lockwood
Apr 24 '13 at 17:46
add a comment |
@sim I fell back to this solution but first I needed to disable apparmor in Ubuntu. It was restricting ntpd access to the drif file. Today the drift files appear to be up to date and the jitter is reasonable if not a bit higher that I'd like. Using tcpdump I see traffic on the LAN that I really don't understand but will work on that question later.
– Nate Lockwood
Apr 24 '13 at 17:46
@sim I fell back to this solution but first I needed to disable apparmor in Ubuntu. It was restricting ntpd access to the drif file. Today the drift files appear to be up to date and the jitter is reasonable if not a bit higher that I'd like. Using tcpdump I see traffic on the LAN that I really don't understand but will work on that question later.
– Nate Lockwood
Apr 24 '13 at 17:46
@sim I fell back to this solution but first I needed to disable apparmor in Ubuntu. It was restricting ntpd access to the drif file. Today the drift files appear to be up to date and the jitter is reasonable if not a bit higher that I'd like. Using tcpdump I see traffic on the LAN that I really don't understand but will work on that question later.
– Nate Lockwood
Apr 24 '13 at 17:46
add a comment |
I've usually setup systems so that as part of their power up routine that they'd initially run ntpdate and get their time bootstrapped from the local time server just so they aren't initially wildly off. Then just start up ntpd using it's default options.
For example, at the end of the file: /etc/rc.local add the following line:
/etc/init.d/ntpd stop
ntpdate <local time server>
/etc/init.d/ntpd start
It's hacky but does the job. I found this thread on Server fault that discusses reasons for not turning NTP into Frankenstein's monster by making it do something it was never meant to do, mainly keep precise time.
If you're really bent on getting precise time I think you'd be better off with this: Precise Time Protocol. There is an open source project that has implemented the PTP protocol, aptly named The Linux PTP Project.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 20 '13 at 23:24
slm♦slm
254k71536687
ntpdateis not needed;ntpdcan set the time at startup.
– Martin Schröder
Apr 21 '13 at 13:06
@Martin For about two minutes after start up the NTP appliance will not have a "lock" on a GPS satellite and will give its best estimate from its battery powered clock. Will I need to compensate for this?
– Nate Lockwood
Apr 21 '13 at 17:47
1
If you look at the iburst link that @Martin provided the first paragraph covers your question. ... "The iburst option does several checks quickly as soon as the daemon is started and whenever the server is unreachable if you have that in your configuration. The burst option does several checks quickly whenever the server is reachable."
– slm♦
Apr 21 '13 at 17:51
@MartinSchröder Between the two of you and a 10 year old Linux guide I'm starting to get a handle on this. Where, that is, what file starts ntpd on boot and is that the spot that ntpd is told how often to check the ntp server?
– Nate Lockwood
Apr 21 '13 at 20:59
@NateLockwood: ntpd checks the server as often as needed: You don't have to tell it the interval. Please read the FAQ. The startup of ntpd is handled by your OS - typically it should "just work".
– Martin Schröder
Apr 21 '13 at 21:45
add a comment |
I've usually setup systems so that as part of their power up routine that they'd initially run ntpdate and get their time bootstrapped from the local time server just so they aren't initially wildly off. Then just start up ntpd using it's default options.
For example, at the end of the file: /etc/rc.local add the following line:
/etc/init.d/ntpd stop
ntpdate <local time server>
/etc/init.d/ntpd start
It's hacky but does the job. I found this thread on Server fault that discusses reasons for not turning NTP into Frankenstein's monster by making it do something it was never meant to do, mainly keep precise time.
If you're really bent on getting precise time I think you'd be better off with this: Precise Time Protocol. There is an open source project that has implemented the PTP protocol, aptly named The Linux PTP Project.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 20 '13 at 23:24
slm♦slm
254k71536687
ntpdateis not needed;ntpdcan set the time at startup.
– Martin Schröder
Apr 21 '13 at 13:06
@Martin For about two minutes after start up the NTP appliance will not have a "lock" on a GPS satellite and will give its best estimate from its battery powered clock. Will I need to compensate for this?
– Nate Lockwood
Apr 21 '13 at 17:47
1
If you look at the iburst link that @Martin provided the first paragraph covers your question. ... "The iburst option does several checks quickly as soon as the daemon is started and whenever the server is unreachable if you have that in your configuration. The burst option does several checks quickly whenever the server is reachable."
– slm♦
Apr 21 '13 at 17:51
@MartinSchröder Between the two of you and a 10 year old Linux guide I'm starting to get a handle on this. Where, that is, what file starts ntpd on boot and is that the spot that ntpd is told how often to check the ntp server?
– Nate Lockwood
Apr 21 '13 at 20:59
@NateLockwood: ntpd checks the server as often as needed: You don't have to tell it the interval. Please read the FAQ. The startup of ntpd is handled by your OS - typically it should "just work".
– Martin Schröder
Apr 21 '13 at 21:45
add a comment |
I've usually setup systems so that as part of their power up routine that they'd initially run ntpdate and get their time bootstrapped from the local time server just so they aren't initially wildly off. Then just start up ntpd using it's default options.
For example, at the end of the file: /etc/rc.local add the following line:
/etc/init.d/ntpd stop
ntpdate <local time server>
/etc/init.d/ntpd start
It's hacky but does the job. I found this thread on Server fault that discusses reasons for not turning NTP into Frankenstein's monster by making it do something it was never meant to do, mainly keep precise time.
If you're really bent on getting precise time I think you'd be better off with this: Precise Time Protocol. There is an open source project that has implemented the PTP protocol, aptly named The Linux PTP Project.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 20 '13 at 23:24
slm♦slm
254k71536687
I've usually setup systems so that as part of their power up routine that they'd initially run ntpdate and get their time bootstrapped from the local time server just so they aren't initially wildly off. Then just start up ntpd using it's default options.
For example, at the end of the file: /etc/rc.local add the following line:
/etc/init.d/ntpd stop
ntpdate <local time server>
/etc/init.d/ntpd start
It's hacky but does the job. I found this thread on Server fault that discusses reasons for not turning NTP into Frankenstein's monster by making it do something it was never meant to do, mainly keep precise time.
If you're really bent on getting precise time I think you'd be better off with this: Precise Time Protocol. There is an open source project that has implemented the PTP protocol, aptly named The Linux PTP Project.
edited Apr 13 '17 at 12:13
Community♦
1
answered Apr 20 '13 at 23:24
slm♦slm
254k71536687
edited Apr 13 '17 at 12:13
Community♦
1
edited Apr 13 '17 at 12:13
Community♦
1
edited Apr 13 '17 at 12:13
Community♦
1
1
answered Apr 20 '13 at 23:24
slm♦slm
254k71536687
answered Apr 20 '13 at 23:24
slm♦slm
254k71536687
answered Apr 20 '13 at 23:24
slm♦slm
254k71536687
254k71536687
ntpdateis not needed;ntpdcan set the time at startup.
– Martin Schröder
Apr 21 '13 at 13:06
@Martin For about two minutes after start up the NTP appliance will not have a "lock" on a GPS satellite and will give its best estimate from its battery powered clock. Will I need to compensate for this?
– Nate Lockwood
Apr 21 '13 at 17:47
1
If you look at the iburst link that @Martin provided the first paragraph covers your question. ... "The iburst option does several checks quickly as soon as the daemon is started and whenever the server is unreachable if you have that in your configuration. The burst option does several checks quickly whenever the server is reachable."
– slm♦
Apr 21 '13 at 17:51
@MartinSchröder Between the two of you and a 10 year old Linux guide I'm starting to get a handle on this. Where, that is, what file starts ntpd on boot and is that the spot that ntpd is told how often to check the ntp server?
– Nate Lockwood
Apr 21 '13 at 20:59
@NateLockwood: ntpd checks the server as often as needed: You don't have to tell it the interval. Please read the FAQ. The startup of ntpd is handled by your OS - typically it should "just work".
– Martin Schröder
Apr 21 '13 at 21:45
add a comment |
ntpdateis not needed;ntpdcan set the time at startup.
– Martin Schröder
Apr 21 '13 at 13:06
@Martin For about two minutes after start up the NTP appliance will not have a "lock" on a GPS satellite and will give its best estimate from its battery powered clock. Will I need to compensate for this?
– Nate Lockwood
Apr 21 '13 at 17:47
1
If you look at the iburst link that @Martin provided the first paragraph covers your question. ... "The iburst option does several checks quickly as soon as the daemon is started and whenever the server is unreachable if you have that in your configuration. The burst option does several checks quickly whenever the server is reachable."
– slm♦
Apr 21 '13 at 17:51
@MartinSchröder Between the two of you and a 10 year old Linux guide I'm starting to get a handle on this. Where, that is, what file starts ntpd on boot and is that the spot that ntpd is told how often to check the ntp server?
– Nate Lockwood
Apr 21 '13 at 20:59
@NateLockwood: ntpd checks the server as often as needed: You don't have to tell it the interval. Please read the FAQ. The startup of ntpd is handled by your OS - typically it should "just work".
– Martin Schröder
Apr 21 '13 at 21:45
ntpdate is not needed; ntpd can set the time at startup.– Martin Schröder
Apr 21 '13 at 13:06
ntpdate is not needed; ntpd can set the time at startup.– Martin Schröder
Apr 21 '13 at 13:06
@Martin For about two minutes after start up the NTP appliance will not have a "lock" on a GPS satellite and will give its best estimate from its battery powered clock. Will I need to compensate for this?
– Nate Lockwood
Apr 21 '13 at 17:47
@Martin For about two minutes after start up the NTP appliance will not have a "lock" on a GPS satellite and will give its best estimate from its battery powered clock. Will I need to compensate for this?
– Nate Lockwood
Apr 21 '13 at 17:47
1
1
If you look at the iburst link that @Martin provided the first paragraph covers your question. ... "The iburst option does several checks quickly as soon as the daemon is started and whenever the server is unreachable if you have that in your configuration. The burst option does several checks quickly whenever the server is reachable."
– slm♦
Apr 21 '13 at 17:51
If you look at the iburst link that @Martin provided the first paragraph covers your question. ... "The iburst option does several checks quickly as soon as the daemon is started and whenever the server is unreachable if you have that in your configuration. The burst option does several checks quickly whenever the server is reachable."
– slm♦
Apr 21 '13 at 17:51
@MartinSchröder Between the two of you and a 10 year old Linux guide I'm starting to get a handle on this. Where, that is, what file starts ntpd on boot and is that the spot that ntpd is told how often to check the ntp server?
– Nate Lockwood
Apr 21 '13 at 20:59
@MartinSchröder Between the two of you and a 10 year old Linux guide I'm starting to get a handle on this. Where, that is, what file starts ntpd on boot and is that the spot that ntpd is told how often to check the ntp server?
– Nate Lockwood
Apr 21 '13 at 20:59
@NateLockwood: ntpd checks the server as often as needed: You don't have to tell it the interval. Please read the FAQ. The startup of ntpd is handled by your OS - typically it should "just work".
– Martin Schröder
Apr 21 '13 at 21:45
@NateLockwood: ntpd checks the server as often as needed: You don't have to tell it the interval. Please read the FAQ. The startup of ntpd is handled by your OS - typically it should "just work".
– Martin Schröder
Apr 21 '13 at 21:45
add a comment |
Thanks for contributing an answer to Unix & Linux Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2funix.stackexchange.com%2fquestions%2f73116%2ftime-synchronization-of-machines-on-lan-to-gps-ntp-server-on-the-lan%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
Welcome to SE, your question is very well thought out and asked, based on that there's no way you could be a SYSADMIN 8-).
– slm♦
Apr 20 '13 at 22:16
By saying I have a NTP server on the LAN I do not mean that it is a computer acting as a NTP server. It's an appliance that gets its time from GPS and makes it available to NTP requests through the NTP port.
– Nate Lockwood
Apr 21 '13 at 17:40
Thanks for the clarification. Given that I'd think either mine or Martin's answer would work OK for you. Probably would lean towards Martin's answer as the way to go if I was you.
– slm♦
Apr 21 '13 at 17:47