XNTPD - Is this normal?

[Ng Shee Yong]

Hi all,

Need some help on xntpd messages found in the /var/adm/syslog/syslog.log.

We have a HP R-390 server (HPUX 10.20) connected to a HP 58503B GPS Time and Frequency Reference Receiver. The R-390 itself is a ntp server using GPS receiver as it's time source.

The recent leap second issue made us scrutinised the syslog more carefully for ntp related messages.

We found that even prior to Jan 1 2006, multiple xntpd 'syncronisation lost' and 'syncronised' messages were logged every few hours. Below is a part of the messages found. For more details please refer to attached file.

Dec 24 11:26:53 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 11:26:54 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 11:28:04 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 15:20:29 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 15:20:30 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 15:21:40 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 15:32:29 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 15:32:36 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 15:33:40 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 15:39:57 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 15:40:04 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 15:49:24 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 15:50:05 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 15:50:12 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 16:02:28 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 16:03:09 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 16:03:10 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 16:06:12 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 16:07:41 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 16:07:48 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 16:12:52 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 16:16:13 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 16:16:20 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 16:17:24 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 16:33:49 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 16:33:56 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 16:35:00 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 24 16:38:21 sdf_r11 xntpd[2320]: synchronisation lost
Dec 24 16:38:22 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 24 16:39:48 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 25 05:58:53 sdf_r11 xntpd[2320]: synchronisation lost
Dec 25 05:59:00 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 25 06:00:04 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 25 06:15:25 sdf_r11 xntpd[2320]: synchronisation lost
Dec 25 06:15:26 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 25 06:16:36 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 25 06:30:21 sdf_r11 xntpd[2320]: synchronisation lost
Dec 25 06:30:22 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 25 06:31:48 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 25 06:33:49 sdf_r11 xntpd[2320]: synchronisation lost
Dec 25 06:33:56 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 25 06:35:16 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 25 08:03:09 sdf_r11 xntpd[2320]: synchronisation lost
Dec 25 08:03:10 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 25 08:04:20 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 26 04:51:09 sdf_r11 xntpd[2320]: synchronisation lost
Dec 26 04:51:10 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 26 04:52:20 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 26 10:33:17 sdf_r11 xntpd[2320]: synchronisation lost
Dec 26 10:33:24 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 26 10:34:28 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0
Dec 26 19:13:49 sdf_r11 xntpd[2320]: synchronisation lost
Dec 26 19:13:56 sdf_r11 xntpd[2320]: synchronized to LOCAL(1), stratum=3
Dec 26 19:15:16 sdf_r11 xntpd[2320]: synchronized to GPS_HP(1), stratum=0


Is this behaviour normal?

Appreciate any englightenment on this issue.

Thanks in advance.

[Devender Khatana]

Hi,

If the error is from your ntp server then the time synchronization is not proper and it is losing synchronization causing these error messages in the syslog.log.

One possible major reason for this is the lost of link between your server and the reference server. Is this right? You can continuously monitor the link conclude if it is stable or not.

HTH,
Devender

[Steven E. Protter]

Shalom,

Normal? No.

Critical? No.

Networking between the ntp server and your box may have been lost. The ntp server may be an old microsoft box that does not comply with unix standards.

You should have this checked.

SEP

[Ng Shee Yong]

Thanks for the replies.

Just to clarify.

The system is a HP R-390 server running on HPUX 10.20. It is connected thru RS-232 to a HP GPS receiver.

The system is configured as a ntp server using the GPS receiver as the reference source.

Any idea why synchronisation can be lost using a standard RS-232 cable?

[Henk Geurts]

i would check the cable and the connections....
replace the cable if you have a spare....

regards.

[Ng Shee Yong]

Thanks for the advices.

As for the serial cable, i've tested it by connecting it to a laptop that has the GPS receiver test program. I'm able to run up the test program, check on the GPS receiver status and even send test commands without problem.

The funny part is that the symptoms will occur every few hours a day.

Any docu on the sync process i can readup on?
I'll like to know what scenarios or events could have resulted in lost of sync.

[Bill Hassell]

This may not be HP-UX but the GPS server. Does the GPS receiver have any logs? If the receiver is indoors, the antenna may be blocked by the building's structure and you have only a marginal signal.

[Ng Shee Yong]

The receiver is in-door but the antenna is mounted outdoors.

The test program i used only shows instantenous status of the receiver. No logs were retrievable.

During the afternoon i was checking on the GPS reeiver, I'm seeing consistently 6-7 Sat found by the receiver and GPS lock is active.

Self-tests status on the receiver are all green too.

Is there any document i can refer to for the details of the xntpd sync handshaking?