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Verifying NTP Configuration on XenServer

Issue
How to verify whether the NTP is configured correctly on a redundant system by Stratus.

Product Line
XenServer by Stratus.

Environment
Power Monitoring Expert installed on redundant system from Stratus.
XenServer

Cause
Verify all hardware clocks and complete NTP configurations. PVMs (virtual machines) might later jump their clocks forward or backward during reboot, migration, or failover scenarios. This can occur even if the local (Windows) clocks are corrected and maintained from a legitimate, external source.

Resolution
To verify whether the NTP is configured correctly, query the NTP and hardware clock setups on XenServer domain 0.
Use the following command on all XenServers in the pool to verify that time is synchronized with an external NTP server:
# ntpstat;date;hwclock

The output would look like (an example):
synchronised to NTP server (10.31.0.11) at stratum 4
time correct to within 125 ms
polling server every 64 s
Mon Nov 12 08:45:48 EST 2012
Mon 12 Nov 2012 08:45:49 AM EST -0.899689 seconds
#

The output confirms the following:
• Output from ntpstat indicates that time is synchronised (first three lines).
• Output from date (fourth line) indicates the correct time and time zone.
• Output from hwclock (fifth line) indicates the same time and time zone as the date command, to within 1 second.
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