DST time end impact on SAP systems / Should keep ON or OFF

[Former Member]

Hi,

I have some queries on DST end which is going to happen after 2 days.

Our systems are going to face Daylight saving time (DST) end on Nov 3 2013 02:00 AM. Hence we are afraid of question that whether we should keep our systems ON or we should keep our systems down for those "double hours" during DST end.

Following are some details to understand further on our concern,

Our systems are located in Pittsburgh, USA. So currently we are in EDT time zone and on coming Sunday we will be on EST time zone after DST end.

We have ECC,BW,PI & SOL systems; And all of them are based on Netweaver Rel. & Having kernel Rel. 720

We have also set "Variable Summer time rules" as per Note 919538

In our all systems parameter "zdate/DSTswitch_contloctime" exist and its current value is ON

Now we have found three options to tackle DST end situation,

1. Two hour downtime method: Completely avoid running SAP system during this double hour.

2. One hour downtime method: Note 102088

3. Zero downtime method: Use the default “stretched time”. / Available default in all the systems (http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/00269ed5-9f37-2f10-8686-f28792c19...)

Now the problem is our management has decided not to shutdown any system, and during the DST end our systems runs many standard & functional jobs. So here we are scared on the result i.e. whether our system will operate as usual or there will be conflict with time after DST end. As we are not understanding point 3 Zero downtime method clearly.

Kindly let me know some definite response if you are US customer & have face this kind of scenario in past & are also going to face this now.

Thanks for your kind response.

Best Regards,

Kiraang.

[Former Member · Accepted solution]

Hi,

Fortunately we decided to keep our systems ON & we are now proved correct. We also had written to SAP but they had suggested us to keep systems down & if that is not possible then make sure that no jobs run during those double hours. But we didn't took any action & all gone as normal.

No dumps, No error logs, & No job failure due to Time issue.

Below is for reference of people who would like to know on this,

at 01:00 EDT clock has started running with half speed, 1 hr. before EST

At OS level clock will automatically switch to 01:00 EST on 02:00 EDT

DST has end & EST time has been started now (EST time is correct wall clock time)

Now system time will match with real clock time

EST time zone entry will get disappear.

Time zone has now been adjusted to EST at 02:00 AM.

Now it will run the clock with normal speed.

No job failure, No dumps, & No error logs related to Time.

Regards,

Kiraang.

[tams_uracs · Accepted solution]

Dear Kiraang,

I'm in similar situation as You were. Could You please help a little bit: what notes did You implemented?

Thank You in advance,

T.

[Former Member · Accepted solution]

Hi,

If you are on kernel 720 then you don't need to do anything. SAP system will manage DST change.

No downtime is require.

Regards,

Kiraang.

[tams_uracs · Accepted solution]

Hi,

Thanks, we are above then kernel version 720.

Have You changed anything in STZBC?

Regards,

Tamas

[Former Member · Accepted solution]

Hi,

Again, Nothing to change & nothing to worry if you are above 720 kernel

Regards,

Kiraang.

[zobair]

Dear Kiraang,

Very good post. Thank you.

I have a question:

What is the added value to maintain "Fixed Summer time rules"?

For example, please check note "2232043 - No daylight saving time in Uruguay from year 2015 onwards".

Is there an added value to maintain the table "TTZDF"?

When this table is used?

If the "Fixed Summer time rules" is not maintained, do you think that the SAP system will react correctly?

Thank you for your reply,

Zobair

[Former Member]

Hi,

I believe Uruguayan government has decided to abolish DST from this year putting the country in UTC−3 all year round. Hence you need to set your system timezone settings as mentioned in SAP note  2232043 (You don't need to refer 198411).

Just do the changes as mentioned in note 2232043 and do not edit table "TTZDF" as concern changes will be automatically reflected in that table only for Fixed Summer time rule.

You have to make the require settings in all the respective clients (000,001,066, $$$) otherwise there can be inconsistency.

In short, as per note 2232043, you need to do following changes in all the clients.

1. Delete the Variable Summer time rule for DST Rule "URUGU"

2. Add the Fixed Summer time rule for DST Rule "URUGUA" for the past 5 years

You can execute report TZONECHECK to cross check the timezone consistency after the changes.

Regards,

Kiraang.