Business as Usual – Even During an Upgrade

Software upgrades and migrations usually have a negative side effect for companies: downtime. Applications and their business processes are simply unavailable for a certain period of time. IT personnel must consider these interruptions of ongoing operations when they schedule upgrades.
Many companies can perform upgrades and migrations on weekends when operations are shut down and no critical processes need to run. But the situation is quite different for production industries – chemical companies and firms that harvest raw materials – that operate around the clock. Because a company’s applications are unavailable during downtime, critical processes also come to a standstill. For example, a company can’t post orders or reorder materials.
In the case of just-in-time deliveries that are most prevalent in the automobile industry, these kinds of system outages can lead to a plant shutdown in the worst case – usually with significant financial losses. And a vendor must then generally put up with it. In the oil industry, gushing oil wells can’t be shut off for a specific period. These industries, in particular, need to be able to perform upgrades or migrations without hampering their ongoing operations.

Critical processes handicapped

So far, only two procedures have been available for upgrades or migrations of SAP R/3 applications: a standard upgrade and a time-optimized upgrade from SAP. Both involve shutting down business processes.
System downtime for standard upgrades from SAP usually lasted up to 24 hours, regardless of the type of application and size of the database. As a result, only a couple of dates a year make sense for system conversions. And the conversions run the risk of extended downtime if something doesn’t go according to plan. In the worst case, a company has to perform a rollback – resetting the application to an earlier status. But that can also mean a failure of the entire project.
To limit downtime, SAP has developed a time-optimized upgrade procedure, the system switch upgrade. This approach performs time-consuming upgrade steps, such as import phases, DDIC (Data dictionary), and activation phases, including the comparison of changes during production to reduce downtime to a few hours. But this procedure requires additional system resources, which makes it unusable for many projects.

Downtime equals zero

REALTECH AG is the only consulting firm for SAP that offers a service, Zero Downtime, that can perform upgrades and migrations without interrupting system operations. New technologies like SAP NetWeaver Exchange Infrastructure (SAP NetWeaver XI) and the Interface Manager from REALTECH AG enable this new approach.
Before the upgrade, a copy of the productive SAP solution is created, Users work with the copy during the conversion. Data can then be imported into the new system consistently, and users are switched back to the updated solution. The production system is unavailable only for two short moments: when users are directed to the copy and back. They can continue their work as soon as they log on again.

Upgrades without limitations

Zero Downtime is not a standard solution; it is executed as an individual project at each company. Because production continues to run, the time and length of the upgrade or migration are unimportant.
Preparations for Zero Downtime begin up front with a value scan that compares the costs of the procedure with those that would be caused by the unavailability of the production landscape. The consultants work with clients to identify critical business processes – those that could lead to a standstill of production, like Supply Chain Management. The SAP transactions that must be available for specific users on the system copy can then be derived from the business processes. The selections must be made carefully because the implementation of each transaction involves a great deal of development effort.
To guarantee a seamless upgrade, the complete procedure – switching to the copy, recording data, and switching back to the original – is tested ahead of time, and the consistency of data in both systems is checked.
The productive system is copied by cloning the database with storage techniques. If the techniques are unavailable, users access the shadow database. Users execute all important transactions on the system copy during the upgrade or migration. All transaction data is recorded while the transactions are executed. Temporary intermediate storage of the data in the database (persistence) and mapping to the new data structures occurs with SAP NetWeaver XI or with REALTECH’s software interface manager, IM/3. SAP NetWeaver XI requires its own infrastructure, but IM/3 is installed in the application as an SAP add-on and uses the resources of the existing infrastructure.
The recorded data is imported when the network is switched back to the original system. Scheduling and comprehensive monitoring functions guarantee correct posting. With SAP NetWeaver XI, the runtime workbench or the computer center management system (CCMS) handles monitoring. REALTECH’s interface manager, IM/3, provides its own integration monitor. The imported current data can be processed immediately.
With Zero Downtime, the required follow-up work can be performed after system optimization without interrupting ongoing operations. This work includes creating the upgrade path, importing new programs, and customizing. Extensive and qualitative tests of the new application are performed before users are switched back to the original applications.

Numerous updates coming up

According to a current study by RAAD-Consult, about 70 percent of SAP customers are planning upgrades of their SAP applications in 2006. Upgrade preparation would be much easier if critical business processes remained available during the conversion. Who would profit the most from such an approach? Companies that operate around the clock and that have to consider the financial effects of upgrades and migrations.

Dr. Harald Sussek
Dr. Harald Sussek