33
votes
ntpd vs. systemd-timesyncd - How to achieve reliable NTP syncing?
systemd-timesyncd does no clock discipline: the clock is not trained or compensated, and internal clock drift over time is not reduced. It has rudimentary logic to adjust poll interval but without ...
- 420
11
votes
Mint 18.1 - A whole lot of "Soliciting pool server xxx.xxx.xxx.xxx"
The messages mean your ntpd server is looking for more time sources to sync to. Seeing a couple of them is expected, especially after reconnecting to the network after an outage or a restart, but if ...
- 166
11
votes
Chrony 3.1 refuses to sync with ntp server
There is a similar bug in RH Bugzilla that was closed as notabug. The issue is a combination of poor time server and a change in defaults for newer chrony to not use them.
https://bugzilla.redhat.com/...
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10
votes
How to keep Debian internal clock synchronized (with NTP servers)?
For Debian GNU/Linux 10 (Buster), 11 (BullsEye), 12 (BookWorm) and next major versions:
The systemd-timesyncd (aka: timesyncd, aka: SystemD-TimeSyncD) is a lighter-weight & simpler alternative of ...
- 233
10
votes
How does Linux use a real time clock?
I can respond to some of these points, including the title.
[...] which always correlate with systemd-timesyncd updating the system clock. By this I mean that the very first syslog message after a ...
- 53.5k
8
votes
Accepted
How does Linux use a real time clock?
Thanks very much to sourcejedi for this answer. This really led me to find the right answer.
Answer to the question
How does Linux use a real time clock to maintain the system clock?
It does so ...
- 21k
8
votes
Accepted
ntp won't work on read-only Raspberry Pi
I found this question while facing a similar issue.
The issue turned out to be that systemd's PrivateTmp feature does not work in a read-only configuration.
Be sure to install ntp and ntpdate
sudo ...
- 196
7
votes
Accepted
ntpd not running
To check the status of ntp you should use:
systemctl status ntp
By modifying the /etc/ntp.conf you should restart the service through:
systemctl restart ntp
The ntpstat report Unable to talk to NTP ...
- 69.8k
7
votes
Accepted
Should I disable systemd-timesyncd if ntp is installed?
Running both at the same time is not recommended. Both services might be using difference ntp servers with slight difference in time. So your server will experience time corrections very frequently: ...
- 6,887
6
votes
Difference between chronyd and ntpd
The Red Hat documentation here has a good comparison of Chrony and NTP and says "Chrony should be preferred for all systems except for the systems that are managed or monitored by tools that do not ...
- 61
6
votes
Difference between chronyd and ntpd
This site comparing chronyd vs ntpd vs openntpd suggests that chronyd has more flexibility in configuring a slewing settings.
- 136
6
votes
Accepted
ntpd does not properly update drift by itself
For some reason, your OS clock is being very inaccurate. Normally ntpd would keep it in correct time by slewing it, i.e. telling a slow clock to "speed up" to make it catch up with real time,...
- 114k
6
votes
Accepted
Check status of 11-Minute Kernel mode using adjtimex
(Just to clear possible confusion by anyone reading this answer: when Linux is running, there are (usually) two clocks: the "main" clock is the system clock, which is usually CPU-based. The ...
- 114k
5
votes
Is there a way to smear a time correction made by ntp?
With thanks to the pointers from dr01 I found the answer in a mailing list response here. The key difference was the terms I was using. ntp uses "step" over "jump" and "slew" over "smear".
...
- 1,634
5
votes
Is there a way to smear a time correction made by ntp?
NTP should automatically take care of this, without brutal clock jumps or anything.
You can run ntpd -q to synchronize the time once and quit.
Note that if the clock skew is too big (>1000 secs), ...
- 32.4k
5
votes
Accepted
chronyd or ntpd + What are the benefits when using chronyd?
A short answer is: ntpd is replaced by chronyd as the default NTP daemon in RHEL 7. It is a different implementation which is able to synchronize the system clock faster and with better accuracy.
A ...
- 1,216
5
votes
Accepted
NTPd multicast setup
Stratum 16 indicates the NTP server does not believe it has a valid time because it has no connection to any configured time source. In order to make ntpd on the server system trust the system's local ...
- 114k
5
votes
Is ntpd working?
There are several ways to determine whether ntpd is working:
Use ntpq -p (or ntpq -pn to save time by skipping DNS lookups).
This is what it looks like when NTP is working:
host-a ~ # ntpq -p
...
- 14.7k
4
votes
What are the ports needs to be opened for NTPD?
If you're going to run ntpd , you need to fix your network/firewall/NAT so that ntpd can have full unrestricted access to UDP port 123 in both directions.
- 174
4
votes
Accepted
ntpd vs. systemd-timesyncd - How to achieve reliable NTP syncing?
Just to clarify differences between the three most commnly used deamons:
timesyncd and ntpd are both time synchronization services available in Linux, but they differ significantly in terms of ...
- 197
4
votes
Accepted
How often (and when) does NTPD update the time?
If you change the clock underneath NTP while it's running, it will either start to slew the clock back - if it's not too far out - or simply give up in disgust and exit.
If you do change the clock a ...
- 128k
4
votes
Accepted
NTP service shown "inactive" with 'timedatectl status'
Quoting from @don_crissti's comment to directly answer OP's query:
You don't need the ntpd.service if you're using the timesyncd one. I use the latter on several desktops that don't even have the ntp ...
- 114k
4
votes
NTP client cannot sync date from a specific Server
The problem you're seeing is that the local client time and the remote server time are too far apart. The maximum offset is 1000 seconds; your machines are 26,000 seconds apart!
The reason for this ...
- 49.3k
3
votes
Chrony 3.1 refuses to sync with ntp server
If you have a windows based NTP server, maybe this will be a fix for you (It worked for me in a similar problem):
https://chrony.tuxfamily.org/faq.html
3.4. Using a Windows NTP server? A common issue ...
- 31
3
votes
Chrony 3.1 refuses to sync with ntp server
For chrony 3.1.
We've pieced together a solution based on the following thread, but for a concise, simple to check answer try the following. Check the status of the time sync you receive with ...
- 131
3
votes
how do you set up a linux client to use ntp information provided through dhcp?
It really depends on the network-setup/dhcp/NTP components you are using and for which combination your distribution did integration work.
As of 2020, at least some distributions consider Chrony as ...
- 59.7k
3
votes
Time drift and wrong timezone within NTP configuration
If your /etc/localtime is pointing to /usr/share/zoneinfo/EET, that timezone definition includes European Summer Time (= European DST) and between the last Sunday of March and the last Sunday of ...
- 114k
3
votes
ntpq does not print the list of the peers immediately
It is possible that ntpq is trying to resolve DNS for the name of the NTP peers and that a misconfigured DNS is causing the timeout and delay of 5 minutes.
You can confirm that that's the case by ...
- 22.6k
3
votes
How to get timesyncd details?
I assume that you are using Ubuntu or another distro in Debian. timesyncd is a small client-only NTP implementation bundled with systemd releases. Unfortunately, systemd-timesyncd does no clock ...
- 129
3
votes
ntp won't work on read-only Raspberry Pi
Mark Roger's answer works, however I think it is better to user overrides:
echo -e '[Service]\nPrivateTmp=false' > /etc/systemd/system/ntp.service.d/override.conf
Then reboot or maybe systemctl ...
- 41
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