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Frequent clock changes

LS1971
Frequent Advisor

Frequent clock changes

Hi,

on our HPE Moonshot IRF switch I see very frequent clock changes:

SNTP/5/NTP_CLOCK_CHANGE: System clock changed from ...

Comware 7.1.045, Feature 2428 is installed on the switches. The NTP configuration is as follows:

 clock protocol ntp
 sntp enable
 sntp unicast-server 10.0.0.1 source Vlan-interface100
 sntp unicast-server 10.0.0.2 source Vlan-interface100

Both IP addresses being our Windows Domain Controllers. Any ideas why I see this repeated clock changes?

Regards, Leonardo
5 REPLIES
parnassus
Honored Contributor

Re: Frequent clock changes

What are the outputs of

display ntp-service sessions

and

display ntp-service status

commands executed on your IRF stack?

LS1971
Frequent Advisor

Re: Frequent clock changes

<SWITCH>display ntp-service sessions
<SWITCH>display ntp-service status
 Clock status: unsynchronized
 Clock stratum: 16
 Reference clock ID: none
<SWITCH>display sntp sessions
SNTP server     Stratum   Version    Last receive time
10.0.0.1        5         4          Tue, Oct 10 2017 17:20:03.181
10.0.0.2        4         4          Tue, Oct 10 2017 17:20:02.179 (Synced)

Regards, Leonardo
parnassus
Honored Contributor

Re: Frequent clock changes

Just curious, can you provide us results of:

display current-configuration | include ntp

and

display clock

and

display ntp-service trace

and

timesync sntp

commands

LS1971
Frequent Advisor

Re: Frequent clock changes

<SWITCH>display current-configuration | include ntp
 clock protocol ntp
 sntp enable
 sntp unicast-server 10.0.0.1 source Vlan-interface100
 sntp unicast-server 10.0.0.2 source Vlan-interface100
<SWITCH>display clock
17:30:40 MEST Thu 10/12/2017
Time Zone : MET add 01:00:00
Summer Time : MEST 02:00:00 March last Sunday 03:00:00 October last Sunday 01:00:00
<SWITCH>display ntp-service trace
Local host: Not synchronized.

There is no "timesync" command.

Regards, Leonardo
VoIP-Buddy
Trusted Contributor

Re: Frequent clock changes

Leonardo,

Stratus 4 and 5 servers are less accurate time servers.  We always like to see peers that are closer to the Atomic Clock than that. 

Are the servers that 10.0.0.1 and 2 using stable?  Are the Moonshot switches within a reasonable delta from the NTP servers?  If more than a few seconds difference, you should manually set the clocks to be closer to the correct time before you enable NTP again.  NTP doesn't make large time swings.  You have to get it there first and then NTP will deal with the fluctuations.

Regards,

David