Différences

Ci-dessous, les différences entre deux révisions de la page.

--- tech:ntp_temps_horloge_heure [2025/03/28 16:08] – Jean-Baptiste
+++ tech:ntp_temps_horloge_heure [2025/10/24 09:49] (Version actuelle) – Jean-Baptiste
@@ Ligne 13: / Ligne 13: @@
 * Si pb de flux réseau voir [[tunnel_ssh_udp_forward]]
 * https://www.vmware.com/docs/vmware_timekeeping
+* /etc/adjtime ''man 5 adjtime_config''
+* ''man 4 rtc'' (Real-Time Clock)
+* https://kb.meinbergglobal.com/kb/time_sync/ntp/ntp_basics
@@ Ligne 69: / Ligne 72: @@
 ~~~
+#### The systems were using only two NTP servers
+Four NTP servers are recommended. See http://support.ntp.org/bin/view/Support/SelectingOffsiteNTPServers
+"With two, it is impossible to tell which one is better, because you don't have any other references to compare them with. This is actually the worst possible configuration -- you'd be better off using just one upstream time server and letting the clocks run free if that upstream were to die or become unreachable."
+"Use at least 4 NTP servers"
+#### Pour éviter la dérive sur les VM
+** Ou passer à Chrony **
+~~~
+tinker panic 0
+~~~
+"The tinker panic value of 0 tells NTP that no matter what the time offset is, not to panic and exit. This is recommended for virtual machines because virtual machines have no physical clock and can be paused at anytime and started back up hours later."
+Source : https://www.redhat.com/en/blog/avoiding-clock-drift-vms
+Voir :
+* https://documentation.avaya.com/fr-CA/bundle/DeployingSystemManagerinVE_r10.1/page/Timekeeping__NTP_.html
+- Add the following line to the beginning of the ''/etc/ntp.conf'' file
+~~~bash
+tinker panic 0
+~~~
+- Remove or comment the "driftfile"
+~~~bash
+#driftfile /var/lib/ntp/drift/ntp.drift # path for drift file
+~~~
+- Restart the ntpd.service
+~~~bash
+/bin/systemctl restart ntpd.service
+~~~
+Voir https://www.suse.com/fr-fr/support/kb/doc/?id=000021102
@@ Ligne 103: / Ligne 150: @@
 ~~~
+#### Autres
+''/etc/sysconfig/ntp''
+~~~bash
+SYNC_HWCLOCK=yes
+~~~
+This is an option to ntpdate
@@ Ligne 216: / Ligne 273: @@
 ## Autres
+### Timesyncd
+''/lib/systemd/system/systemd-timesyncd.service.d/wsl.conf''
+~~~ini
+# Enable timesyncd on WSL machines
+# so WSL clock is synced on resume from suspend of the host.
+[Unit]
+ConditionVirtualization=
+ConditionVirtualization=|!container
+ConditionVirtualization=|wsl
+~~~
+### Adjtimex
 ~~~bash