18
votes
Force chrony time check
If chronyd isn't already running, a command similar to 'ntpdate
pool.ntp.org' could be (since version 1.30):
chronyd -q 'server pool.ntp.org iburst'
If it's already running and it has some servers ...
- 628
9
votes
Ntpd on local network - Preventing clock drift causing high offsets
A driftfile records the frequency of the local clock, and is a good thing to have to accurately discipline it. Ubuntu /etc/ntp.conf has a driftfile by default.
Appending iburst to the server line ...
- 34.2k
8
votes
Red hat Linux + TIME ZONE CONFIGURATION + details from clock file
With the introduction of RHEL 7 the timezone is managed through systemd, which provides a custom utility to change the timezone: timedatectl
To list all available time zones:
timedatectl list-...
- 81.6k
6
votes
Accepted
hwclock: Cannot access the Hardware Clock via any known method
The problem seems to be connected to clocksource, check available_clocksource:
$ cat /sys/devices/system/clocksource/clocksource0/available_clocksource
tsc hpet acpi_pm
Based on answer to "What does ...
- 2,303
6
votes
Accepted
Red hat Linux + TIME ZONE CONFIGURATION + details from clock file
So the "correct" way to set the clock (at least prior to RHEL 7) is to edit /etc/sysconfig/clock and then run tzdata-update which will then update /etc/localtime; you've just done that step manually.
- 4,811
5
votes
Ntpd on local network - Preventing clock drift causing high offsets
Your lack of a relation between your NTP server's clock time and the real-world UTC time could be the root of your problem. If your NTP server does not have multiple real-world sources (regardless of ...
- 4,651
4
votes
Accepted
AWS EC2 with huge clock drift at boot
There is a decent chance the answer is nowhere or nowhere it can reach. You should look at the Amazon Time Sync Service. This seems to be the recommended method now, because NTP also requires making ...
- 707
4
votes
Completely disable Date and Time sync in a Hyper-V VM
How about unchecking Time synchronization option in Integration Services under VM settings?
- 9,200
4
votes
hwclock: Cannot access the Hardware Clock via any known method
For me, the fix was just to type "sudo" before the command, as the "can't access" actually means it doesn't have perms to access /dev/rtcX. Running it with sudo fixed it by giving ...
- 41
3
votes
Accepted
Ntpd on local network - Preventing clock drift causing high offsets
After trying a few different options on ntpd still having a too big delay, I switched to chrony. My NTP server remained unchanged. Using chrony gave me a latency of <1ms all the time. I increased ...
- 211
3
votes
Completely disable Date and Time sync in a Hyper-V VM
Hyper-V guests always synchronize time with the host on BIOS level during boot. Try to specify the time zone properly, otherwise you can manage time in Active Directory.
You can check the following ...
- 5,896
2
votes
Accepted
How to have WSL think it is in the past?
Because WSL is not a virtual machine, it's always going to be tied to your underlying system time. If modifying your system time on demand is too cumbersome, you only have two options as far as I can ...
- 16.9k
2
votes
Time on Windows servers out and won't stay corrected
The PDCe in the domain should be synced to a reliable external time source.
All other domain clients should be synced to the domain hierarchy.
https://docs.microsoft.com/en-us/windows-server/...
- 111k
2
votes
Accepted
How to Set Up Time Synchronization with NTP on Ubuntu 20.04.1 LTS
Your timedatectl doesn't state
systemd-timesyncd.service active: yes
but
NTP service: active
which suggest you are using NTP, instead.
With Ubuntu 20.04 LTS you could be running Chrony. Try e.g.
...
- 51k
2
votes
How can the local time clock of a server become the NTP time source in a network?
Clocks in general purpose computers are garbage, relative to the accuracy expected in modern devices. Not precisely calibrated, and a server's thermal changes can cause the drift to vary. So it needs ...
- 34.2k
2
votes
No info found about `ethtool -T` output?
-T --show-time-stamping
Show the device's time stamping capabilities and associated PTP hardware clock.
https://linux.die.net/man/8/ethtool
PTP stands for Precision Time Protocol that allows sub-...
- 12.6k
2
votes
Accepted
No info found about `ethtool -T` output?
This is normally output via running ethtool -T <ifname> and indicates the index of the PTP clock. If there are multiple hardware clocks in the system you will see increasing values for this. For ...
- 36
1
vote
No info found about `ethtool -T` output?
PTP - Precision Time Protocol is a protocol used to synchronise clocks throughout a computer network. On a local area network, it achieves clock accuracy in the sub-microsecond range, making it ...
- 81.6k
1
vote
Accepted
How can I verify if time is set correctly on server in my bash script?
You can use command in Linux:
date +%s
and in Windows (PowerShell)
Get-Date -UFormat %s
to get epoch time. Those numbers can be easy compared.
P.S. For Windows you may need to strip the number to ...
- 6,302
1
vote
How "real" is the POSIX clock in a virtual machine?
POSIX (and Linux in general) never really has guaranteed timers in the sense if you put something to sleep you can expect it to wake up at an exactly certain time. You can only ever guarantee that the ...
- 23.9k
1
vote
Is there a way to keep server times in sync to the millisecond, globally?
When you're down to the millisecond range, you can't do it with things like NTP. That is generally only accurate in the tens of milliseconds-range over the internet.
You probably have to go with ...
- 10.2k
1
vote
Accepted
Problems with chronyd Centos 7 all updates applied
I have ensured that ntp is functioning on ESX, it apears it was not
configured correctly so I assume that when chronyd went offline it
grabbed the time from ESX which was wrong.
Yes, you need to ...
- 34.2k
1
vote
Compute Engine VM clock runs fast and gains 15 seconds per hour (or about 1 second per each 4 minutes)
Upgrade?
First - you notice that 5 minutes off cause problems. Any admin will tell you that this is because Kerberos hates ticket time offsets more than that on windows ;)
Your main problem is ...
- 52k
1
vote
Completely disable Date and Time sync in a Hyper-V VM
In addition to the answer that suggests to stop "Windows Time" and "Hyper-V Time Synchronization Service", I found that you not only need to stop it, but to deactivate the "Windows time" service. If ...
1
vote
Completely disable Date and Time sync in a Hyper-V VM
For anyone still looking for this answer, there are 2 services in the VM that need to be stopped - "Windows Time" and "Hyper-V Time Synchronization Service". When I stop (and disable) both of these ...
- 11
1
vote
FreeBSD: how to syncronize the system clock with the hardware clock in bash?
See answer 1 (below?) for general advice.
In order to make sure that ntpd will set the clock it should be run with the -g switch. Or if you do it by hand ntpd -g -n. The last switch is to make sure ...
1
vote
FreeBSD: how to syncronize the system clock with the hardware clock in bash?
Check sysctl machdep.disable_rtc_set. It should be 0, and hardware clock is set automatically every time settimeofday() is called. Then, if the ntpd is running, you don't have to set hardware clock ...
- 51k
1
vote
NTP service stopped in centos7.1 linux machine
Speculative answer: on-board clock might drift if power is cut. Maybe on-board battery is nearly dead. If machine is powered down for a while and power is cut off then the time set upon reboot might ...
- 193
1
vote
Synchronize clock with NTP while online, and with RTC while offline?
Set it up to use the pseudo-clock "local clock". Add this to ntp.conf
server 127.127.1.1 iburst
fudge 127.127.1.1 stratum 8
server 127.127.1.1 is the pseudo-clock aka the local RTC.
iburst ...
- 161
Only top scored, non community-wiki answers of a minimum length are eligible