The Software Update Manager updates your system using a system cloning and switch procedure. This procedure installs a copy of the system, the shadow system, in parallel with the original system. The shadow system is used to update the affected software components and to install the additional components, while the original system is still in production operation.

Operating two instances in parallel places increased demands on free space in the file system, in the database, and on the system resources. No precise guidelines can be given for the duration of the update procedure. The duration of the system cloning depends on a great extent on the amount of data, the database system, and the hardware and can take several hours. Although the system can still be used in production operation, you have to take into account a possible performance decrease during this cloning process. If necessary, some parameters in the production system must be adjusted to enable you to operate the production and the shadow systems in parallel.

The following figure shows the process flow of the update procedure with the major steps of the procedure.

When you install add-ons, use the procedure relevant for their delivery method. Add-ons delivered through a stack.xml configuration file are installed during the procedure by the Software Update Manager.

The complete update procedure is divided into roadmap steps. In these roadmap steps, the following actions take place:

• Get Roadmap

  The Software Update Manager analyzes the source system and the database, and it collects by means of a dialog sequence the needed information for the wanted scenario to assemble the roadmap.

• Extraction

  The Software Update Manager extracts the required software.

• Configuration

  In the Configuration roadmap step, you enter information required for the upgrade procedure such as information about software components, add-ons, and support packages that you want to include as well as information about the shadow system.

• Checks

  The Software Update Manager checks if the operating system and database version of your source release match the requirements of the target release. It also checks some application-specific requirements.

• Preprocessing

  In this roadmap step, the Software Update Manager creates the shadow system. This shadow system is then used for various update activities while you can still use the original system in production operation. The Software Update Manager builds up the shadow system by cloning parts of the original system. All tables of the SAP NetWeaver Application Server are needed as shadow tables to operate the shadow system. The shadow system is used to perform the modification adjustment of the ABAP Dictionary objects and the activation of new ABAP Dictionary objects that are part of the update. Finally, the Software Update Manager performs the shadow import and writes directly into the shadow tables. Modifications to the contents of the original tables are indicated by triggers. These tables are copied and imported during downtime.

• Execution

  In this roadmap step, the switch to the target system takes place. The Software Update Manager completes the copy import action during downtime for all tables with set triggers. The EU_SWITCH phase completes the switch to the new system. All tables prepared in the shadow system are copied to the target system. The KX_SWITCH_1 phase switches the SAP kernel. The ENVFILES phase changes the environment for the new release. The PARCONV_UPG phase converts the application table, and the phase TABIM_UPG imports the remaining data. Finally, the XPRAS_AIMMRG phase starts the XPRAs required by the system update.

• Postprocessing

  The Software Update Manager saves the log files and prompts you to start with certain follow-up activities. Furthermore, it runs cleanup activities and generates the evaluation.

• Finalization and Summary

  The Software Update Manager removes files and directories that are no longer required and completes the upgrade. Moreover, it displays a feedback form on the SUM UI and prompts you to send your feedback to SAP for technical analysis. For more information, see Evaluating the Software Update Manager.