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Adjusting for Time Change - Use DAYLIGHT_SAVINGS.com or AUTO_DLIGHT_SAV
Posted: Thu Nov 07, 2019 5:03 pm
by vmskostoff
When administering multiple nodes of VAX, Alpha, and Itaniums, time change in the Spring and Fall becomes a significant event. Looking for a simpler and effective method to administer time change on OpenVMS. Ideally a method to set once and forget it. Versions vary from 7.3 to 8.4.
Option 1: DAYLIGHT_SAVINGS.COM - Answer the questions and it goes to SYS$BATCH
Option 2: AUTO_DLIGHT_SAV - Change to 1. Any other changes? Reliable?
Option 3: ???
Appreciate any and all input.
Re: Adjusting for Time Change - Use DAYLIGHT_SAVINGS.com or AUTO_DLIGHT_SAV
Posted: Mon Nov 11, 2019 3:03 am
by brianreiter
We set AUTO_DAYLIGHT_SAV to 1 and then, for any process which needs to know about the change in daylight savings time we use the $SET_SYSTEM_EVENT service to get the notification. For example.
Code: Select all
$SET_SYSTEM_EVENT (SYSEVT$C_TDF_CHANGE,
ast_system_event,
,
,
SYSEVT$M_REPEAT_NOTIFY,
tdf_handle
);
$HIBER;
In one case we use this method to restart the NTP service, effectively ensuring that synchronisation is maintained.
cheers
Brian
Re: Adjusting for Time Change - Use DAYLIGHT_SAVINGS.com or AUTO_DLIGHT_SAV
Posted: Mon Nov 11, 2019 10:03 am
by vmskostoff
So by setting AUTO_DLIGHT_SAV and having NTP running on the node, the node correctly adjusts forward or backward an hour? That is all that is required?
There is no annual checking or setting of any other command procedures?
No reason to adjust the TDF?
Re: Adjusting for Time Change - Use DAYLIGHT_SAVINGS.com or AUTO_DLIGHT_SAV
Posted: Tue Nov 12, 2019 5:24 am
by brianreiter
Not sure NTP is actually essential for the time change to occur, we only force a resynchronisation to be on the safe side. We actually use the TCPIP$NTP_SYSTARTUP.COM file to use NTPDATE prior to starting the NTP service.
Code: Select all
(CATC2)>ty SYS$SYSROOT:[SYS$STARTUP]TCPIP$NTP_SYSTARTUP.COM
MC SYS$SYSTEM:TCPIP$NTPDATE.EXE NTPSERVER
Other than the initial testing we haven't experienced any problems for at least a decade, unlike the VAX days when it used to cause all sorts of havoc.