Daylight Savings coming 1

[normntwrk]

In light of the upcoming daylight savings time change I thought I might script something to help us with this as quite a few of our customers are on 4.3.3.

I have also tried this at the command line but nothing happens, I expected it would write it to the /etc/environment file

chtz EST5EDT,M3.2.0/1:00:00,M11.1.0/1:00:00

export $TZ

Also tried it without the specific time (1:00:00)
Any thoughts

Norm

 

[samirm]

Here is the information which we have ...
==========================================

AIX O/S updated to support 2007 Daylight Saving Time change



AIX O/S updated to support 2007 Daylight Saving Time change - (default)
The Energy Policy Act of 2005 (Public Law 109-58) was passed by the United States Congress on July 29, 2005 and signed into law on August 8, 2005. This law changes the time-change dates for Daylight Saving Time in the United States. Beginning in 2007, DST will begin on the second Sunday in March and end on the first Sunday in November.

IBM has released updates to the AIX 5L operating systems to support this change. The updates should be applied prior to March 11, 2007.

AIX 5L Version 5.3
IBM recommends installing Technology Level 4 or later. The update is also available as a specific fix by installing the fix for APAR IY75211
Filesets: bos.rte.libc.5.3.0.40 and bos.adt.prof.5.3.0.40

AIX 5L Version 5.2
IBM recommends installing Technology Level 8 or later. The update is also available as a specific fix by installing the fix for APAR IY75213
Filesets: bos.rte.libc.5.2.0.85 and bos.adt.prof.5.2.0.85

AIX 5L Version 5.1 (Out of support)
The update is available as a specific fix by installing the fix for APAR IY75214
Filesets: bos.rte.libc.5.1.0.70 and bos.adt.prof.5.1.0.70

To download these fixes, visit:
Quick links for AIX fixes

AIX 4.3.3 DST Workaround (Out of support)
You can manually specify when to start and stop DST by setting the TZ environment variable in the /etc/environment file. An example for the US Central timezone follows:

TZ=CST6CDT,M3.2.0,M11.1.0
"M3.2.0" means to go on DST starting in month 3 (March), week 2, and Day 0 (Sunday).
"M11.1.0" means 1st Sunday in November.
NOTE: Reboot the system before March, 2007 so all processes running will pick up the new time change.


For additional information on the impact of Daylight Saving Time on Java that ships with AIX, see: Changes to Daylight Saving Time will affect IBM Java and AIX.


Sam

 

[normntwrk]

yeah I have that too, I just thought the chtz command would take care of it for me and that I could script it but it doesn't seem to work on 4.3.3 or 5.3.0 in a script or at the command line. At the command line It is supposed to return a 0 if successful (it doesn't)

Norm

 

[normntwrk]

I'll be darned it worked after all! I thought an echo $TZ would show the new setting but it did actually write it to the file after all! Perhaps the new $TZ will show after a reboot.

PATH=/usr/bin:/etc:/usr/sbin:/usr/ucb:/usr/bin/X11:/sbin:/usr/java14/jre/bin:/usr/java14/bin
TZ=EST5EDT,M3.2.0/1:00:00,M11.1.0/1:00:00

Cool!

Norm

 

[p5wizard]

chtz EST5EDT,M3.2.0/1:00:00,M11.1.0/1:00:00

export $TZ

the first command changes (should change) the TZ value in /etc/environment

the second command is a) unnecessary and b) erroneous

correct syntax is:

export TZ

but the TZ var should already be marked for export so re-exporting doesn't do a thing. What you do need is a reboot of the machine(s) so that all system daemons (especially cron) become aware of the new TZ value.


HTH,

p5wizard

 

[normntwrk]

thanks on the export info

Norm

 

[samirm]

p5wizard,

Please get a star.

Sam

 

[appelq]

Shouldn't the time variable be set to 2:00:00?
The time change takes effect at 2am, not 1am, no?

 

[normntwrk]

Probably so, I just copied the TZ info from IBM's website somewhere as is

I can't imagine any impact either way as nothing is going on at 1 or 2 AM on these servers

Thanks

Norm

 

[handle789]

The example from the IBM doc using 1:00 for 1AM is not correct. I checked with IBM support and they said that the default time is 2AM. So you can leave the time value blank in the TZ value and the zone switch will start at the default time of 2AM. You only need the month/week/day values. You will need to reboot the box before the 03/11 for the new TZ value to be picked up.

After you typed in the new TZ value in the environment file, type "su -", "echo $TZ", and you will see the new TZ setting. But the box will need to be rebooted before the 11, according to IBM support.

 

[handle789]

BTW, is any one out there familiar with the IBM Java DST APARs IY85293 for Java 1.3.1 and IY84053 for Java 1.4? Thanks.

 

[bi]

If you have applications that use Java and they use date and time functions and the filesets aren't up to the level in the APARs, you need to apply the APARs. Or you need to install the latest version of Java. The APARs don't cause a boot, but the Java processes have to be stopped and restarted.

There are actually 4 APARs: one each for Java 1.3.1 32 bit, 1.3.1 64 bit, 1.4 32 bit and 1.4 64 bit.

In addition, there is a Java patch utility that you need to apply to those instances of Java that have not been installed with the installp command. Check out

http://download.boulder.ibm.com/ibmdl/pub/software/dw/jdk/dst/readme.htm.

No need to use the patch utility on Java installed with installp. (In fact, IBM told me not to use the utility in those instances.)