Daylight Saving Time (DST) change can affect IBM Tivoli Workload Scheduler, JSC and TDWC

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Abstract

The present Technote explains how to be sure that TWS environment is up to date in regards of an upcoming DST changes.


The Energy policy Act changes the effective dates of DST. Beginning in 2007, DST start and end dates will be as follows for the US:

Start Date: Second Sunday of March (11 March 2007)
End Date: First Sunday of November (4 November 2007)
Systems or applications that process dates and times could be affected by this change. If not addressed,time and date calculations could be incorrect.

Content

Below are the major DST policy changes that have occurred in the past few years:
2011 - Russia Abolishes Daylight Saving Time in Russia:
The new legislation eliminates the yearly switch between standard time and daylight saving time. The country will turn its clocks one hour forward for the last time on March 27, 2011 making daylight saving time Russia's new standard time.

2007 - United States, Canada, Bermuda
Energy Policy Act of 2005 has changed the effective dates of US, Canada and Bermuda Daylight Saving time (DST) starting from 2007: The daylight saving time begins on the second Sunday of March and ends on the first Sunday of November.

IMPORTANT NEWS for AIX 7.1 / 6.1

*************************************************************************************************
System time may not change properly at DST start/end dates on AIX 7.1 and AIX 6.1
See the following Technote:
http://www-01.ibm.com/support/docview.wss?uid=isg3T1013017

AIX systems or applications that use the POSIX time zone format may not change time properly at Daylight Savings Time start or end dates. Applications that use the AIX date command, or time functions such as localtime() and ctime(), on these systems may be affected.

Systems and applications using the Olson time zone format are NOT affected. Do not take any action if you use Olson format.

This issue impact Master Doman Managers and FTAs.

For customer running on AIX 6.1 due to a previous problem related to the use of Olson time zone format (see the section "Important APAR and notices" at the end of this document),it is required to remain to POSIX format and to install the relative AIX Maintenance level.

*************************************************************************************************


"What could happen if I do not update my systems?"
Systems or applications that rely on date or time processing functions could make incorrect calculations. Calendar, scheduling, or synchronising problems could arise where systems use date or time stamps, or if dates or times are processed or manipulated in any way. In short, if your system makes date or time calculations, you may experience calculation errors.


"How to determine if the TWS environment will be impacted by an incoming DST change?"
The TWS environment can be impacted by a DST changes whether Timezones are enabled or not.
To determine if Timezones are enabled in TWS, look at the value of the global option enTimezone using optman:

<TWSHOME>/optman ls

  • Timezone not enabled
If all TWS workstations reside in a timezone not impacted by the DST change:
>>>> it is not required to patch TWS.

If JSC and/or TDWC reside in a timezone not impacted by the DST change:
>>>> it is not required to patch them

If the RDBMS (both client and server) used by TWS resides in a timezone not impacted by the incoming DST change:
>>>> it is not required to patch the RDBMS.

In all other cases you need to patch the TWS environment.

  • Timezone enabled
If all TWS workstations reside in a timezone not impacted by the DST change and you do not have time dependencies expressed using the changing timezone:
>>>> it is not required to patch TWS.

If the RDBMS (both client and server) used by TWS resides in a timezone not impacted by the incoming DST change:
>>>> it is not required to patch the RDBMS.

In all other cases you need to patch the TWS environment.


"What component needs to be patched?"
  • Operating Systems and Database.
    To correctly manage the DST change, TWS requires that the Operating System and the RDBMS (both client and server) are correctly patched.
    This prerequisite is valid whether Timezones are enabled or not.
    The operating system prerequisite applies to the TWS Master and the TWS agents. Refer to the support page of your Operating System or RBMDS to determine the correct patch level for each.
  • Master Domain Manager and Backup Master(s)
    These components have to be patched if at least one of the TWS workstations is working in a time zone impacted by the DST change, or if you have time dependencies expressed using the affected timezone.

    >>>> For the Master Domain Manager and Backup Master there are two considerations:

    1. Timezone table of TWS
    2. Timezone table of the embedded WebSphere Application Server (eWAS)

    If a TWS Fix Pack containing the Timezone table's update for the eWAS is not available yet, run the appropriate level of "IBM Time Zone Update Utility for Java" (JTZU) to update the Timezone table of the eWAS.

    See the section below entitled "List of Fixpacks including DST fixes" to determine which TWS Fix Pack updates the Timezone table of the eWAS.

    NOTE
    By default JnextPlan without parameters extends the plan of one day.
    This means that usually it extends the plan of 24 hours, instead during the DST switch off/on is extends the plan of 23/25 hours, because it is able to manages the DST.
    The same if JnextPlan is run with the option -days 1
    While if you run JnextPlan -for 2400, even during the DST switch on/off the plan will be extended of 24 hours exactly without take care of the DST switch.

    IBM Time Zone Update Utility for Java, JTZU Tool:
    http://www-128.ibm.com/developerworks/java/jdk/dst/index.html

    IMPORTANT:
    TWS calculates in advance when a jobstream has to be added to the production plan. This information is stored in a database table (a.k.a. Pre-Production plan).
    If a DST patch (regardless if it is for the TWS Master, operating system. or RDBMS) is installed a few days before the DST time change, it is possible that the pre-production plan has been calculated using the incorrect timezone table.

    You can check this by getting the value of maxlen globaloption using:
    <TWSHOME>/optman ls

    If the DST patch has been installed during the maxlen time, follow the procedure below:

    1. Determine the StartOfDay value using optman ls
    2. Execute the following:
    optman chg sd=<same value that you get from optman ls>
    3. At the next Plan creation, the Pre-Production Plan will be automatically re-calculated and jobstreams will be added to the Symphony with the correct time.

  • TDWC and JSC
    These components have to be patched if at least one of the TWS workstations is working in a time zone impacted by the DST change, or if you have time dependencies expressed using the affected timezone.

    >>>> JSC/TDWC you need to consider only the Timezone tables of Java/eWas

    In case a JSC/TDWC Fix Pack containing the timezone table's update for Java/eWas is not available yet:
    you have to run the appropriate level of JTZU to update the Timezone table.
  • TWS Connector
    These component has to be patched if at least one of the TWS Workstations is working on a time zone impacted by the DST change, or if you have time dependencies expressed using the affected timezone.

    >>>> you need to take care only of the Timezone table of eWas

    If a TWS Fixpack containing the timezone table's update for eWas is not availabe yet, run the appropriate level of JTZU to update the Timezone table.
  • TWS Agent
    For a TWS Agent, you need to only consider the Timezone table of TWS.
    Usually these tables are updated through a TWS Fix Pack.
    If a TWS Fix Pack containing the necessary timezone table's update is not available yet, see below in this page how to obtain the modified timezone tables.

    A TWS Agent needs to be patched when:

    - the Agent works in the impacted timezone;
    - the Agent hosts a Standard Agent (SA) or Extended Agent (XA) working in the impacted timezone;
    - the Agent or its SA/XA has jobs that belong to a jobstream for a different workstation and this workstation works in the impacted timezone;
    - the Agent is a Domain Manager and one of its FTA works in the impacted timezone;
    - the Agent is used to submit ad-hoc jobs or jobstream for a workstation working in one of the impacted time zones;
    - the Agent is used to submit ad-hoc jobs or jobstreams by command line using time dependencies that refer to the impacted timezone.

-------------------------------------------------------------------------------
"List of TWS Fixpacks that include DST fixes"

United States DST
---------------------------------------------------------------------------------

TWS v8.3.0
  • TWS v8.3.0 Fix Pack 02 (for TWS Engine and eWAS)
  • JSC v8.3.0 Fix Pack 02

TWS v8.4.0
  • TWS 8.4.0 Fix Pack 01 (for TWS Engine and eWAS)
  • JSC 8.4.0 Fix Pack 01

TWS v8.5.x
  • TWS v8.5.x GA (for TWS Engine and eWAS)
  • TDWC v8.5.x GA

TWS v8.6
  • TWS v8.6 GA (for TWS Engine and eWAS)
  • TDWC v8.6 GA

---------------------------------------------------------------------------------

Canada, Bermuda, Brazil, Mexico DST
---------------------------------------------------------------------------------

TWS v8.3.0

  • TWS v8.3.0 Fix Pack 04 (for TWS Engine and eWAS)
  • JSC v8.3.0 Fix Pack 04

TWS v8.4.0
  • TWS v8.4.0 Fix Pack 01 (for TWS Engine and eWAS)
  • JSC v8.4.0 Fix Pack 01

TWS v8.5.x

  • TWS v8.5.x GA (for TWS Engine and eWAS)
  • TDWC v8.5.x GA

TWS 8.6.
  • TWS v8.6 GA (for TWS Engine and eWAS)
  • TDWC v8.6. GA
-------------------------------------------------------------------------------

Russia Saving Time

-------------------------------------------------------------------------------
TWS v8.3.0

  • For TWS Engine apply the modified timezone table (see the link below)
  • For eWAS, TDWC, JSC use at least the JTZU version 1.6.11h

TWS v8.4.0
  • For TWS Engine apply the modified timezone table (see the link below)
  • For eWAS, TDWC, JSC use at least the JTZU version 1.6.11h

TWS v8.5.0
  • TWS 8.5.0 Fix Pack 03 (for TWS Engine only)
  • For eWAS, TDWC, JSC use at least the JTZU version 1.6.11h

TWS v8.5.1
  • TWS 8.5.0 Fix Pack 03 (for TWS Engine only)
  • For eWAS, TDWC, JSC use at least the JTZU version 1.6.11h
TWS v8.6
  • TWS 8.6 Fix Pack 01 (for TWS Engine only)
  • For eWAS, TDWC, JSC use at least the JTZU version 1.6.11h

-------------------------------------------------------------------------------


PROCEDURE TO APPLY THE MODIFIED TIMEZONE TABLE

UNIX
1. Download the tar file related to your TWS version / platform
2. Create a directory of your choice
mkdir <YOUR_DIR>
3. Untar the tar file into <YOUR_DIR>
cp zoneinfo_<platform>.tar <YOUR_DIR>
cd <YOUR_DIR>
tar -xvf zoneinfo_<platform>.tar
4. Create a backup copy of <TWSHOME>/zoneinfo directory
5. Remove all files under <TWSHOME>/zoneinfo directory
rm -rf <TWSHOME>/zoneinfo/*
6. Copy new timezone table
cp -pR <YOUR_DIR>/* <TWSHOME>/zoneinfo/
7. Set ownership
chown -R <tws_user>:<tws_group> <TWSHOME>/zoneinfo
8. Set permission
chmod -R 755 <TWSHOME>/zoneinfo

WINDOWS
1. Download the zip file related to your TWS version / platform
2. Create a directory of your choice
mkdir <YOUR_DIR>
3. Unzip zip file into <YOUR_DIR>
4. Create a backup copy of <TWSHOME>\zoneinfo directory
6. Copy all files and directories of <YOUR_DIR> into <TWSHOME>\zoneinfo
NOTE: By overwriting the files, new files will inherit the previous rights and ownership

---------------------------------------------------------------------------------

TWS timezone table for Russian change
Use the following URL(s) for a convenient download of the data:

ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_AIX.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_HPIA64.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_IRIX.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_LINUX_IX86.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_LINUX_PPC.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_LINUX_S390.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_OSF.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_SEQUENT.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_SOLARIS.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.3-zoneinfo_WIN32.zip

ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_AIX.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_HPIA64.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_HPUX.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_LINUX_IX86.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_LINUX_PPC.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_LINUX_S390.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_LINUX_X86_64.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_SOLARIS.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_SOLARIS_IX86.tar
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_WIN32.zip
ftp://ftp.emea.ibm.com/fromibm/tivoli/8.4-zoneinfo_WIN64.zip



"Summary table"
The TWS environment can be impacted by a DST changes whether Timezones are enabled or not.

TWS Release / Fixpack Engine table WAS table
TWS 8.6 GA tzdata2010o tzdata2010m
TDWC 8.6 GA N.A. tzdata2010m
TWS 8.5.1 Fixpack03 tzdata2011i tzdata2010l
TDWC 8.5.1 Fixpack03 N.A. tzdata2010l
TWS 8.5.0 Fixpack03 tzdata2011i tzdata2010l
TWS 8.4.0 Fixpack06 tzdata2010o tzdata2010l

"Important APARs and notices related to Timezone and DST"

  • >>>>>>>>> AIX 7.1 / 6.1 <<<<<<<<<<<<

    System time may not change properly at DST start/end dates on AIX 7.1 and AIX 6.1

    See the following Technote:
    http://www-01.ibm.com/support/docview.wss?uid=isg3T1013017

    AIX systems or applications that use the POSIX time zone format may not change time properly at Daylight Savings Time start or end dates. Applications that use the AIX date command, or time functions such as localtime() and ctime(), on these systems may be affected.

    Systems and applications using the Olson time zone format are NOT affected. Do not take any action if you use Olson format.
  • AIX 6.1

    See the following Technote:
    https://www-304.ibm.com/support/docview.wss?uid=isg1fixinfo105720

    AIX 6.1 uses ICU (International Components for Unicode) libraries to manage the timezone of the system, and these ICU libraries are in conflict with the Tivoli Workload Scheduler ones.
    As a consequence Tivoli Workload Scheduler does not correctly recognize the timezone of the local workstation,
    Workaround:
    Export the TZ environment variable before starting the Tivoli Export the TZ environment variable before starting the Tivoli Workload Scheduler to the old POSIX format, for example CST6CDT.
    This is an example of a POSIX name convention instead of an Olson name convention
    (for example America/Chicago).
    This avoids the new default TimeZone management through the ICU libraries in AIX 6.1,
    by switching to the old POSIX one (as is in AIX 5.x).

    The OLSON issue has been solved on AIX 6.1, the problem is resolved at TL 7 SP 4 and later.

  • TWS scheduling in Epoch

    Starting from 8.5.1 Fixpack03 and 8.6 Fixpack01, during the day when DST will switch for a workstation, TWS will start scheduling in epoch. This allow to remove the following limitation that were present into the product:

    -
    Ambiguity for jobs scheduled when Daylight Saving Time switches off
    If a job stream or a job run on a timezone where the Daylight Saving Time (DST) switches off, that is the clock is put one hour back, and if you define a time dependency for such job streams or jobs in relation to another timezone, it might happen that this time dependency occurs during the second, repeated time interval.
    In this case the time dependency would be resolved during the first time interval.
    Now Tivoli Workload Scheduler recognizes that the time dependency occurs on the second, repeated time interval and resolves it accordingly.

    - EVERY JOB is now Daylight Saving Time aware
    If the EVERY keyword is defined for a job when the Daylight Saving Time switches off, that is the clock is put one hour back, the job does not run during the second, repeated time interval.
    Now the command EVERY JOB is DST aware and it runs also during the second, repeated time interval.

    No user action is required to activate these behaviours, it is only needed to install 8.5.1 Fixpack03
    on the Master Domain Manager and on the interested Agents.
  • IV14317 - JS SUBMITTED FROM TDWC DURING THE DST FALL SWITCH DOES NOT START AT FIRST OCCURRENCE

    This APAR is included in the following Fixpacks:
    8.5.1 Fix Pack 04
    8.6 Fix Pack 01
  • Java incompatibility with three letters timezone: MST, EST, AGT

    Refer to the following Technote:
    http://www-1.ibm.com/support/docview.wss?uid=swg21250634

    Consider that Java is going to deprecate the three letter timezones, so for a long term plan you should substitute the "three letters timezone" with the relative long name format.

  • IZ72279 - DURING THE FALL DST SWITCH, SCHEDULES BETWEEN 0100 AND 0200 ARE NOT PUT INTO THE SCHEDULE ON THE DAY OF DST SWITCH ONLY

    This APAR is included in the following Fixpacks:
    8.3 Fix Pack 09
    8.4 Fix Pack 05
    8.5 Fix Pack 02
    8.5.1 Fix Pack 01
    8.6 GA

  • IZ73054 - TWSMERGE NOT CORRECTLY SWITCHED

    This APAR is included in the following Fixpacks:
    8.4 Fix Pack 05
    8.5 Fix Pack 02
    8.5.1 Fix Pack 01
    8.6 GA

  • IZ66678 - DURING THE FALL DST SWITCH JOBS DURING DST WINDOW ARE DELAYED RUNNING

    This APAR in included into the following Fixpacks:
    8.3 Fix Pack 09
    8.4 Fix Pack 05
    8.5 Fix Pack 01
    8.5.1 Fix Pack 01
    8.6 GA



Change History
31 Oct 2011 Added Info for Russia DST change
1 Nov 2006 Text Updated
20 Oct 2006 Initial draft created

Related information

TWS v8.2 Fix Pack 10
JSC v1.4 Fix Pack 02
TWS v8.2.1 Fix Pack 2
TWS v8.3.0 Fix Pack 2
JSC v8.3.0 Fix Pack 2
TzData eFix available for APAR # IY95963
Recommended Fixes for TWS

AIX DST.doc

Product Alias/Synonym

Maestro
TWS
ITWS

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Document information


More support for:

Tivoli Workload Scheduler

Software version:

8.3, 8.4, 8.5, 8.5.1, 8.6

Operating system(s):

AIX, AS400, HP-UX, Linux, Linux/390, Solaris, SunOS, UNIX, Windows 2000, Windows 2003, Windows XP

Reference #:

1248101

Modified date:

2013-05-14

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