Time issues on R740 & 7.2/7.3
We have had issues on our two R740s with clocks becoming out of sync even with NTP servers setup. Our first assumption was that we had set something up wrong... These were good references to rule that out and show we had an actual issue:
NTP Sync:
https://support.citrix.com/article/CTX226572
Tips by Tobias:
https://discussions.citrix.com/topic/381709-xenserver-70-and-ntp/
Restarting the NTP client synced the time, but within a few days the times would both be wrong (slow) by dozens of minutes and sometimes even up to an hour or more. Both hosts would also be significantly different. While one would be off by 45 minutes the other might be off by an hour and 15 minutes. This was obviously something more and needed to be escalated to support.
Here is what came from the support call:
The agent changed the current clock source from tsc to xen by running the following at the console.
To make this change permanent, he added the above line on rc.local (located at /etc/rc.d/rc.local) and changed permission of rc.local to 755 by running:
This is a workaround, but they indicated they will have a hotfix coming to resolve. Once the hotfix is released (or included in 7.4?) the process to revert back is to do the following:
Remove the line echo "xen" > /sys/devices/system/clocksource/clocksource0/current_clocksource from rc.local and change the permission back to 644 by running:
and reboot the host.
Hopefully this helps someone else having this issue!
NTP Sync:
https://support.citrix.com/article/CTX226572
Tips by Tobias:
https://discussions.citrix.com/topic/381709-xenserver-70-and-ntp/
Restarting the NTP client synced the time, but within a few days the times would both be wrong (slow) by dozens of minutes and sometimes even up to an hour or more. Both hosts would also be significantly different. While one would be off by 45 minutes the other might be off by an hour and 15 minutes. This was obviously something more and needed to be escalated to support.
Here is what came from the support call:
The agent changed the current clock source from tsc to xen by running the following at the console.
echo "xen" > /sys/devices/system/clocksource/clocksource0/current_clocksource
To make this change permanent, he added the above line on rc.local (located at /etc/rc.d/rc.local) and changed permission of rc.local to 755 by running:
chmod +x /etc/rc.d/rc.local
This is a workaround, but they indicated they will have a hotfix coming to resolve. Once the hotfix is released (or included in 7.4?) the process to revert back is to do the following:
Remove the line echo "xen" > /sys/devices/system/clocksource/clocksource0/current_clocksource from rc.local and change the permission back to 644 by running:
chmod 644 /etc/rc.d/rc.local
and reboot the host.
Hopefully this helps someone else having this issue!
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