Recently the clocks changed for Europe Region on Oct 29 and now Time Zones are also updated in all SAP systems based on their configuration.

There are still different opinions whether we should take restart of SAP systems. Most of us are saying Yes, we should take restart to avoid double hour in SAP ECC as it will impact BG Jobs, Posting and other important task.

Some other talks, if your system is running in GMT and UTC time zone then there is no need of restart.

Let me share my experience during DST change –

We have not taken any restart of ECC system, our SAP system is running on HANA 2.0 SPS05 with NW 7.40.

Time Zone – GMTUK time zone. (CET -1), (UTC +1)

According to SAP Note – 2375952 – Daylight saving time: Is a restart needed for Winter to Spring change, parameter zdate/DSTswitch_contloctime is sufficient to handle this situation if it’s enable(on) in the system.

By default, this parameter is on since kernel 6.40.

Profile Parameter

According to parameter description – 

When transferring from summer to winter time, an hour takes place twice. The SAP system can only run for this time as a whole or in part under certain conditions. If it is running, this profile parameter specifies how the system time (SY-UDATUM, SY-TUZEIT) behaves. If the parameter is set to ‘off’, the ‘doubled hour’ is also displayed twice. If the parameter is set to ‘on’, the doubled hour is ‘expanded’, so that no doubled times can arise, that is, for example:

•off: 2:00, 2:30, 2:00, 2:30, 3:00.
•on : 2:00, 2:15, 2:30, 2:45, 3:00

The purpose of the parameter is to slow down the time during the double hour, so that the SAP server will built up a time lag of up to 30 minutes with respect to the official time. if VM time is changing to 2 min then it will effect only 1 min in System Time.

You can also observe error in work process trace but system will not get shutdown neither you get any dump ZDATE_LARGE_TIME_DIFF

Work Process Trace

Now all 2 hours passed, system clock only change itself to 1 hour and adjust accordingly with the new time zone without any double hour issue.

DST Complete

Important Notes to consider –

2375952 – Daylight saving time: Is a restart needed for Winter to Spring change

3015840 – Daylight saving time: best practices

2080216 – Check HANA DB for DST switch

102088 – Daylight saving time changeover; standard time, reduction of downtime