Next August 21, Sunday, at 00:00 will be necessary to advance clocks in 1 hour.
We need a patch for tzdata primarily for Red Hat Enterprise 5 and 6.
This change has been addressed in the following update:
The change is not listed among the changes, but the version that we ship in that update is 2011g, which should contain this change. In particular, this is what I see in RHEL 5 mock:
> zdump -v America/Santiago | grep 2011
America/Santiago Sun May 8 02:59:59 2011 UTC = Sat May 7 23:59:59 2011 CLST isdst=1 gmtoff=-10800
America/Santiago Sun May 8 03:00:00 2011 UTC = Sat May 7 23:00:00 2011 CLT isdst=0 gmtoff=-14400
America/Santiago Sun Aug 21 03:59:59 2011 UTC = Sat Aug 20 23:59:59 2011 CLT isdst=0 gmtoff=-14400
America/Santiago Sun Aug 21 04:00:00 2011 UTC = Sun Aug 21 01:00:00 2011 CLST isdst=1 gmtoff=-10800
Please make sure that your system is updated.
This is what we currently ship:
$ ~/src/tzdiff/zidiff.py usr-2011n-2/share/zoneinfo/America/Santiago | grep 2011
Introduced CLT (UTC-4, std) 8th (2nd Sun) May 2011 03:00:00
Introduced CLST (UTC-3, dst) 21st (3rd Sun) Aug 2011 04:00:00