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Modifying Fedora Core 2 to support Daylight Savings Time changes in 2007
How to modify FC2 to support DST changing on March 11, 2007. Our servers are all in Eastern Standard Time, so I only show EST changes, but others should be obvious.
This site has some great practical information. I used the tzdata file available here.
An unpatched system shows:
# zdump -v EST5EDT | fgrep 2007
EST5EDT Sun Apr 1 06:59:59 2007 UTC = Sun Apr 1 01:59:59 2007 EST isdst=0 gmtoff=-18000
EST5EDT Sun Apr 1 07:00:00 2007 UTC = Sun Apr 1 03:00:00 2007 EDT isdst=1 gmtoff=-14400
EST5EDT Sun Oct 28 05:59:59 2007 UTC = Sun Oct 28 01:59:59 2007 EDT isdst=1 gmtoff=-14400
EST5EDT Sun Oct 28 06:00:00 2007 UTC = Sun Oct 28 01:00:00 2007 EST isdst=0 gmtoff=-18000
Note that it shows DST starting on April first, this is an error and shows that the old rules are being used.
Download and untar the new tzdata file into /tmp/zoneinfo, then run:
cd /tmp/zoneinfo
zic -d /tmp/zoneinfo northamerica
Then, copy the updated files to the correct places:
cp -p /tmp/zoneinfo/EST5EDT /usr/share/zoneinfo/EST5EDT
cp -p /tmp/zoneinfo/America/New_York /usr/share/zoneinfo/America/New_York
cp -p /tmp/zoneinfo/EST5EDT /etc/localtime
Once these changes are made, you should see this output:
# zdump -v EST5EDT | fgrep 2007
EST5EDT Sun Mar 11 06:59:59 2007 UTC = Sun Mar 11 01:59:59 2007 EST isdst=0 gmtoff=-18000
EST5EDT Sun Mar 11 07:00:00 2007 UTC = Sun Mar 11 03:00:00 2007 EDT isdst=1 gmtoff=-14400
EST5EDT Sun Nov 4 05:59:59 2007 UTC = Sun Nov 4 01:59:59 2007 EDT isdst=1 gmtoff=-14400
EST5EDT Sun Nov 4 06:00:00 2007 UTC = Sun Nov 4 01:00:00 2007 EST isdst=0 gmtoff=-18000
Note that it now shows DST starting on March 11. Success!