Timezones and TDF/daylight savings

[Fredrik.eriksson]

Hi, This might be a silly question but I can't seem to find any good way to list which is the current Timezone/TDF setting and also anyway to detect if daylight savings is in proper use.

Is there some easy way to do this or do i have to runt SYS$MANAGER:UTC$TIME_SETUP.COM?

Best regards
Fredrik Eriksson

[Oswald Knoppers_1]

I always look at the logicals *zone*:

"SYS$TIMEZONE_DAYLIGHT_SAVING" = "1"
"SYS$TIMEZONE_DIFFERENTIAL" = "7200"
"SYS$TIMEZONE_NAME" = "MEST"
"SYS$TIMEZONE_RULE" = "MET-1MEST-2,M3.5.0/02,M10.4.0/03"

And the value of the sysgen parameter auto_dlight_sav.

This parameter should be set on 1 (unless you use the DTSS component of DECnet-Plus for changing the time.

Regards,

Oswald

[Fredrik.eriksson]

Thanks for the quick reply.

And since I have another question regarding this same subject I'll reuse this :)

I use NTPD to set the time on my OpenVMS 7.3-2 machines. Does the NTPD work with standard time and OpenVMS adds the +X/-X timezone? Or is it NTPD that sets the timezone options?

Quite worried since the machines didn't do it properly when it switched to summer time this year.

Best regards

[Joseph Huber_1 · Accepted solution]

And all together in one command:

@SYS$MANAGER:UTC$TIME_SETUP.COM SHOW

[Joseph Huber_1]

NTP operates on UTC, but uses the SYS$TIMEZONE_DIFFERENTIAL logical to adjust the local VMS time.

So the UTC$TIME_SETUP has to be correct, and the system parameter auto_dlight_sav must be set to make the DST change happen.

[Fredrik.eriksson]

Okey, so basically I need to set the sysgen parameter auto_dlight_save to 1 and it should all be alright?

So steps needed:
1) $ sysgen set auto_dlight_save 1
2) and then a batchjob 26-OCT-2008 03:05:00 that does:
$ @DSA0:[VMS$COMMON.SYSMGR]TCPIP$NTP_SHUTDOWN.COM
$ @DSA0:[VMS$COMMON.SYSMGR]TCPIP$NTP_STARTUP.COM

Then all should be nice 'n dandy? And the only issue is that it won't sync the time properly after DST change between 02.00 and 03.05?

Or is there another way of doing this that's more proper? I've seen something about using "set_vms_logicals" in the ntp configuration files but only seems to bring up pages on google concerning multinet NTP. Is there a differance in NTP clients between multinet ntp and decnet-plus ntp?

Best regards
Fredrik Eriksson

[Brad McCusker]

A couple comments -

You didn't specify the VMS version. That makes a difference with respect to AUTO_DLIGHT_SAV parameter. It's only available on Alpha 7.3 and later and Integrity.

Changing AUTO_DLIGHT_SAV requires a reboot. Don't forget to work that into your plan before the 26th.

Brad McCusker
Software Concepts International
www.sciinc.com

[Brad McCusker]

Whoops - I just saw that you specified the version in a later reply. OK. So don't forget the reboot to set AUTO_DLIGHT_SAV.

[Fredrik.eriksson]

Well there's an issue in rebooting the systems... I can't reboot them before this weekend. Our policy says I need to announce it 2 weeks before, and I was silly enough to remembering that this might become an issue this morning ;P

So then my options are to set the SYS$TIMEZONE_DIFFERENTIAL logical to 3600 instead of the current 7200 and then sort out my auto_dlight_save for the next DST change?

Or can I use the set_vms_logicals option in ntp config?

Best regards
Fredrik Eriksson

[Fredrik.eriksson]

Should have mentioned in my above post that I'm not using TCPWare or Multinet. It's "old fashioned" HP TCP/IP V5.4. Seems to matter atleast when I google since I can't seem to find any information about NTP and automagically changing DST from it.

Best regards
Fredrik Eriksson

[marsh_1]

fredrik,

have you read the instructions on time adjustment in this :-

http://h71000.www7.hp.com/doc/732FINAL/aa-pv5mh-tk/aa-pv5mh-tk.HTMl

[Richard Whalen]

NTPD in MultiNet and TCPware expects auto_dlight_save to be 0 as they handle the adjustment for day light saving time.

On MultiNet and TCPware falling back is more challenging than springing forward as NTPD has to recognize that it has already done it once if it is stepping the clock. If NTPD is slewing the clock, then it slows the clock down and it takes many hours before the full hour is lost.

[Fredrik.eriksson]

Actually hadn't... still doesn't answer my question if ntp can do this for me thou.

I will probably just have to use one of these solutions as a quick fix since it's nearing the end of my work day and I'm not going to be here until monday.

Thanks for all the information and answers thou :) very apprieciated :)

Best regards
Fredrik Eriksson

[Hoff]

Hey, it's TZ season again...

Get the current UPDATE and TZ kits and install them; I haven't looked to see which is the more current of these two. If you're not in the US and have seen recent TZ-related rules changes in your jurisdiction, you'll want to check with your local HP support center, or (sans support contract) roll your own TZ changes.

NTP and OpenVMS and DECnet-Plus DTSS and DCE DTSS are all integrated as of V7.3; OpenVMS handles the rules and the switch in coordination with these packages.

Technically, NTP does not handle the DST switch, and never has; that's not what NTP does. NTP handles the time synchronization, while the local box has the DST rules and the switch. Those rules are now managed by OpenVMS.

While you have this down for the TZs, get a full system disk image copy and apply the mandatory ECOs for OpenVMS.

Here's how to decode the displays and see how your box is set up:

http://64.223.189.234/node/560

From there, you can also find a page on how to roll your own timezone changes using zic and such on V7.3 and later.

[Fredrik.eriksson]

Okey so the daylight_savings.com did not do what I wanted. Had to get up in the middle of the night and sort it out.

Anyway, thanks for all the help and for the next time I'll definitly fix the auto_dlight_save sysgen variable ;)

Best regards
Fredrik Eriksson