Re: Backups and Daylight Savings Time

On Tue, Oct 30, 2007 at 12:21:32PM -0400, Chris Hoogendyk wrote:
> On another backup list I monitor, there was an instance of someone who had 
> their system change time on October 28th. Two issues came out of this. One 
> is that they may have failed to patch their system for the 2007 statutory 
> changes in daylight savings time (it should change on Nov. 4th for many). 
> Two is that they had a backup job scheduled for 2:05am that Sunday. It 
> launched at 2:05, and then 2:05 rolled around again an hour later, 
> whereupon it launched again, waited for the first to complete and then 
> repeated the whole backup.

It took some searching to find this.... To be sure you have the
correct tzdata, run:

/usr/sbin/zdump -v /etc/localtime | grep 2007

Here are the results for America/Denver:

[root@charlesc ~]# /usr/sbin/zdump -v /etc/localtime | grep 2007
/etc/localtime  Sun Mar 11 08:59:59 2007 UTC = Sun Mar 11 01:59:59 2007 MST 
isdst=0 gmtoff=-25200
/etc/localtime  Sun Mar 11 09:00:00 2007 UTC = Sun Mar 11 03:00:00 2007 MDT 
isdst=1 gmtoff=-21600
/etc/localtime  Sun Nov  4 07:59:59 2007 UTC = Sun Nov  4 01:59:59 2007 MDT 
isdst=1 gmtoff=-21600
/etc/localtime  Sun Nov  4 08:00:00 2007 UTC = Sun Nov  4 01:00:00 2007 MST 
isdst=0 gmtoff=-25200

Any tzdata from 2006 or later should work for the US. As usual the
most recent version should be the best.

-- 

Charles Curley                  /"\    ASCII Ribbon Campaign
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