topic Re: NTP sync in Operating System - OpenVMS

NTP sync

AJohnson — Wed, 17 Jan 2007 16:52:08 GMT

I am getting errors when trying to sync an OpenVMS 7.2 machine to a NTP server. The output of ntpdate is below

DMB01:: ntpdate -d SERVER_NAME
server SERVER_NAME (x.x.x.x), port 123
stratum 2, precision -20, leap 00
refid [16843904] delay +0.0255959 dispersion +0.0003957 offset +3600.6403944

transmitted 4, in filter 4
reference time: 17-JAN-2007 16:04:47.65
originate timestamp: 17-JAN-2007 16:48:41.75
transmit timestamp: 17-JAN-2007 15:48:41.11
filter delay: +0.02559 +0.02561 +0.02561 +0.02659
+0.00000 +0.00000 +0.00000 +0.00000
filter offset: +3600.64 +3600.63 +3600.64 +3600.64
+0.00000 +0.00000 +0.00000 +0.00000

Selected server is SERVER_NAME (x.x.x.x) offset +3600.6403944

It seems the reference, originate, and transmit times are all different. What would be the reason behind that?

Re: NTP sync

Andy Bustamante — Wed, 17 Jan 2007 19:33:40 GMT

Looking at this line

filter offset: +3600.64 +3600.63 +3600.64 +3600.64

Check the time zone rules for your system. See sys$manager:UTC$TIME_SETUP.COM if I recall correctly for that version of VMS. Stop NTP, make your changes and restart NTP.

Andy

Re: NTP sync

AJohnson — Wed, 17 Jan 2007 21:13:00 GMT

Thanks, it looks like the tdf was off on that system. How will the US DST date change affect OpenVMS, would I just need to update the TDF again on the new dates chosen for DST rather than letting the system set it?

Re: NTP sync

Hoff — Wed, 17 Jan 2007 22:38:32 GMT

OpenVMS V7.3 and later contain automatic daylight saving time (DST) mechanisms.

OpenVMS V7.2 does not have in-built automatic mechanisms, and it's not supported by NTP. Back then, it was DECnet DTSS (DECdtss) or DCE DTSS that managed the values. Or the DST values were managed manually. You'll likely want to use the DAYLIGHT_SAVINGS.COM procedure to reset the DST, when the time rolls around.

There are some ECOs in this area over various releases, too. Not AFAIK ECOs for the US DST change for V7.2, but still relevant regardless. OpenVMS Alpha V7.3-2 is the next release with current ECO updates still being provided; with prior version support status.

There's a whole section on maintaining the timezone differential factor (TDF) and DST mechanisms on OpenVMS available over in the OpenVMS FAQ. The most current edition of the OpenVMS FAQ is over at http://www.HoffmanLabs.Com/VMSFAQ/

Since you are asking the question (and as you should), run a test or two when you have the opportunity. See if things work the way you expect, and want.

ps: ensure this is an NTP server you are synchronizing with, and not an SNTP server. SNTP servers don't necessarily play well with NTP clients.