Red Hat Knowledgebase

In the calendar year 2006 and 2007, a number of countries have altered the dates on which they observe Daylight Savings Time (DST). The earliest of these changes will occur on March 26, 2006 for those observing Australian DST and in certain parts of the state of Indiana (USA). (Reference: http://aa.usno.navy.mil/faq/docs/daylight_time.html)

The key points being:

1. Australia delaying the end of DST by one week for 2006 only to support the Commonwealth games. Instead of ending at 3am on March 25, 2006 it will end at 3am April 2, 2006.
2. The U.S. Energy Policy Act of 2005 implements change for the US. Starting in March 2007, DST in the United States will begin on the second Sunday in March and end on the first Sunday in November.
3. Canadian Provinces Quebec(QC), Ontario(ON), Nova Scotia(NS), Nunavut(NU), Saskatchewan(SK), Manitoba(MB), New Brunswick(NB), Prince Edward Island(PE), Alberta(AB), British Columbia(BC), Newfoundland and Labrador(NL), Northwest Territories (NT) and Yukon(YK) will follow US DST changes which will come into force in March 2007.
4. Western Australia has introduced a three year trial of DST which has already started on Dec 3rd 2006 and ends on last Sunday in March. A separate article dealing with this change can be found here: http://kbase.redhat.com/faq/FAQ_61_9647.shtm
5. The Bahamas will also follow US DST changes which will come into force in March 2007.

Packages have been released for all three releases of Red Hat Enterprise Linux, and there are a few points in the update that users should be aware of.

Resolution:

Users of Red Hat Enterprise Linux 2.1 have three options to update their machines to a level where these DST updates have been fixed:

1. The initial fix for this requires an update to glibc to the following levels:

   	
   	glibc-2.2.4-32.23
   	glibc-common-2.2.4-32.23
   	glibc-devel-2.2.4-32.23
   	glibc-profile-2.2.4-32.23
   	nscd-2.2.4-32.23
   

   up2date -u <package-name> command can be used to update the packages.

   Now Run the command system-config-date and select the required timezone. This will update the local timezone in /etc/localtime.

2. In July 2006, Red Hat released an updated glibc, which split out the tzdata information into its own package like Red Hat Enterprise Linux 3 and 4. Update to both of these in the same fashion as Red Hat Enterprise Linux 3 and 4, by using the following packages:

   	tzdata-2006m-3.el2_1
   	glibc-common- 2.2.4-32.25
   

   Now Run the command system-config-date and select the required timezone. This will update the local timezone in /etc/localtime.

3. Update tzdata files by hand (without rpm intervention)
   1. Using the archive manager extract the content of the tzdata-2006m-3.el2_1.rpm to a desired directory. This will create a tree structure usr/share/ in that directory.
   2. Replace the current tree structure i.e. /usr/share/zoneinfo with the one that is extracted from the rpm file.
   3. To set the local time, copy the particular file from the /usr/share/zoneinfo as /etc/localtime file. For example: User wants the local time to be set to the New York time, use the command:

      # cp /usr/share/zoneinfo/America/New_York /etc/localtime
      

   If TZ environment variables are being used, updating only /usr/share/zoneinfo will fix this issue.

Once updated, a restart of all the applications relying on /etc/localtime is required. The easiest solution would be to reboot the machine in order to ensure that all the applications are properly updated.

zdump -v /etc/localtime |grep 2007

References:
http://rhn.redhat.com/errata/RHEA-2006-0282.html
http://rhn.redhat.com/errata/RHEA-2006-0279.html