Exadata ILOM – How to Disable Daylight Savings Time (DST) (


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Version 3.1.2.32.b r86441
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[root@bakuexa1celadm01 ~]#
 [root@bakuexa1celadm01 ~]# uname -a
 Linux bakuexa1celadm01.kfsaz.local 2.6.39-400.128.17.el5uek #1 SMP Tue May 27 13:20:24 PDT 2014 x86_64 x86_64 x86_64 GNU/Linux
----Before working
[root@bakudcsprdapp ~]# zdump -v /etc/localtime |grep 2016
 /etc/localtime Sat Mar 26 23:59:59 2016 UTC = Sun Mar 27 03:59:59 2016 AZT isdst=0 gmtoff=14400
 /etc/localtime Sun Mar 27 00:00:00 2016 UTC = Sun Mar 27 05:00:00 2016 AZST isdst=1 gmtoff=18000
 /etc/localtime Sat Oct 29 23:59:59 2016 UTC = Sun Oct 30 04:59:59 2016 AZST isdst=1 gmtoff=18000
 /etc/localtime Sun Oct 30 00:00:00 2016 UTC = Sun Oct 30 04:00:00 2016 AZT isdst=0 gmtoff=14400
---After Working
[root@bakudcsprdapp etc]# mv localtime localtime_org
 [root@bakudcsprdapp etc]# ln -s /usr/share/zoneinfo/Etc/GMT-4 localtime
 [root@bakudcsprdapp etc]# date
 Mon Mar 21 18:31:54 GMT-4 2016
 [root@bakudcsprdapp etc]# zdump -v /etc/localtime |grep 2016
 [root@bakudcsprdapp etc]#
 In this example- our customer is in Azerbaijan, with a timezone of GMT-4
OS files involved:
 /etc/sysconfig/clock
 /etc/localtime
If you look in the directory /usr/share/zoneinfo/Etc on the server, you will see subdirectories by country and even by timezone within the country
 You need to identify what directory, and sub files for your target host
In our example- our customer is on the East coast in Azerbaijan, GMT-4:00
 There are zoneinfo files which have the difference from DST hard coded:
GMT
 GMT0
 GMT-0
 GMT+0
 GMT-1
 GMT+1
 GMT-2
 GMT+2
 GMT-4
 GMT+3
 GMT-4
 GMT-4
 GMT-5
 GMT+5
 GMT-6
 GMT+6
 GMT-7
 GMT+7
 GMT-8
 GMT+8
 GMT-9
 GMT+9
 GMT-10
 GMT+10
 GMT-11
 GMT+11
 GMT-12
 GMT+12
 GMT-13
 GMT-14
 So- the directory/file for them would be:
 /usr/share/zoneinfo/Etc/GMT-4
1. Modify the file /etc/sysconfig/clock to read:
ZONE="Etc/GMT-4"
 UTC=true
 ARC=false
2. Follow these steps to correctly set the file/link /etc/localtime
A. # cd /etc
 B. # rm /etc/localtime
 C. # ln -s /usr/share/zoneinfo/Etc/GMT-4 /etc/localtime
 D. # ls -al localtime
 E. # date
Step D should show the file /etc/localtime as a symbolic link to /usr/share/zoneinfo/Etc/GMT-4
 Step E should return the correct time for Azerbaijan - GMT-4:00
 3. For databases- the only thing you have to make sure of is that the DB OS owner does not have any environmental variables of "TZ" set.
 When your databases start- if they do not see any TZ variables set- they will use the OS time as the DB time.
A. Connect as DB user
 B. Run: # env |grep -i TZ
Step B should show nothing set at the OS as "TZ="
 If there are- then you need to modify the Oracle Db user's profile so this is unset

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