Zero Downtime Option for SAP S/4HANA

The ZDO Concept

This section describes the idea behind the Zero Downtime Option (ZDO) of the Software Update Manager (SUM).

A technical system downtime during an update can be expensive. For this reason, the ideal solution would be to run an update without having a technical system downtime. With the ZDO of SUM, updates of ABAP applications can be run without a technical downtime and with a minimized business downtime.

The idea behind ZDO is to have a bridge-subsystem in parallel with the production system. During the update on the production system, users can continue their work on the bridge-subsystem. The bridge-subsystem reflects the source release and contains all data of the production system that users need to continue their work.

All business transactions of the applications that are enabled for ZDO are fully available during the update. Applications that aren't fully available during the bridge runtime are listed accordingly in SAP Note 2707731 Information published on SAP site. Users can continue, for example, working with transactions, scheduling and running batch jobs, and running print requests.

During the update, the network connections between systems are preserved.

The ZDO approach is beneficial for the following maintenance events:
  • Applying support package stacks
  • Applying feature packages
  • Customer system releases
  • System release upgrades

There are three facts about the Zero Downtime Option:

  1. ZDO comes along with SUM that is the standard tool for software maintenance. There's no additional license needed and no separate tool required.

  2. The database footprint is rather small since not the entire database is cloned. Instead, only selective tables are cloned. The clone tables are determined based on the changes to be performed during the maintenance event.

  3. The technical downtime goes down to a single restart of the application servers. The database, however, isn't restarted. Usually, the restart takes approximately 5 to 15 minutes dependent on the number of application servers.

For more information, see also the blog Leveraging Zero Downtime Option of SUM for SAP S/4HANA Support Package Stack updatesInformation published on SAP site in the SAP Community.