How To
Summary
AIX systems with time zones south of the equator that use daylight saving, with the POSIX format need to adjust the variable to spring forward and fall back at the correct time.
Objective
Ensure AIX time stays in sync and correct with daylight savings changes for systems that use southern hemisphere time zones by using the correct TZ environment variable.
Newly installed AIX systems are likely using the OLSEN time zone format, upgraded systems, or systems built to an older standard might still be using the POSIX format.
There was a performance issue in APAR IV86730 related to the OSLEN format, which is resolved.
The POSIX time zone format is the traditionally used format for AIX systems and provides a slight performance advantage over the Olson time zone format.
The POSIX time zone format is the traditionally used format for AIX systems and provides a slight performance advantage over the Olson time zone format.
If you are still using the POSIX format, the AIX default values:
| NZST-12NZDT | New Zealand | CUT +12 |
| EET-10EETDT | Eastern Australia | CUT +10 |
"The default of the start variable is 02:00:00" is not correct for southern hemisphere time zones.
Environment
AIX Systems with Southern Hemisphere time zones that use Daylight Saving, Australia, New Zealand, Chile, Paraguay
Steps
# chtz TimeZoneInfo
Or
# smitty chtz_user
Then
# grep TZ /etc/environment
After a change to the TZ variable, it is best to restart your system.
- Environment variables are examined when a command starts running.
- The environment of a process is not changed by altering the /etc/environment file.
- Any processes that were started prior to the change to the /etc/environment file must be restarted if the change is to take effect for those processes.
- If the TZ variable is changed, the cron daemon must be restarted, because this variable is used to determine the current local time.
Additional Information
| Southern hemisphere time zones using daylight saving (With official government URL link where found) |
Olsen Format | POSIX Format |
|---|---|---|
| Chile - Santiago | TZ=Chile/Continental TZ=America/Santiago |
TZ=CLT3CLST,M9.2.0/00:00:00,M4.1.0/00:00:00 |
| Paraguay - Asunción | TZ=America/Asuncion | TZ=PYT3PYST,M10.1.0/00:00:00,M3.5.0/00:00:00 |
| Australia - South Australia - SA - Adelaide |
TZ=Australia/South
TZ=Australia/Adelaide
|
TZ=ACST-09:30ACDT,M10.1.0/02:00:00,M4.1.0/03:00:00 |
| Australia - Victoria - VIC - Melbourne |
TZ=Australia/Victoria
TZ=Australia/Melbourne
|
TZ=AEST-10AEDT,M10.1.0/02:00:00,M4.1.0/03:00:00 |
| Australia - New South Wales - NSW - Sydney |
TZ=Australia/NSW
TZ=Australia/Sydney
|
TZ=AEST-10AEDT,M10.1.0/02:00:00,M4.1.0/03:00:00 |
| New Zealand - Auckland / Wellington / Christchurch |
TZ=NZ
TZ=Pacific/Auckland
|
TZ=NZST-12NZDT,M9.5.0/02:00:00,M4.1.0/03:00:00 |
| * Correct at time of writing in 2022, if you are aware of any changes / corrections or if your system is in another Southern Hemisphere time zone, please let me know by using the feedback link. |
Related Information
Document Location
Worldwide
[{"Type":"MASTER","Line of Business":{"code":"LOB08","label":"Cognitive Systems"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SWG10","label":"AIX"},"ARM Category":[{"code":"a8m0z000000cvxSAAQ","label":"Communication Applications-\u003ENTP\/TIMED"}],"ARM Case Number":"","Platform":[{"code":"PF002","label":"AIX"}],"Version":"All Versions"}]
Product Synonym
AIX
Was this topic helpful?
Document Information
Modified date:
21 October 2024
UID
ibm16833126