Lesson 2 of 5
Roadmap steps, uptime, downtime and the shadow system
9 min
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SUM guides the administrator through six roadmap steps: Extraction, Configuration, Checks, Preprocessing, Execution and Postprocessing. Behind each step are many technical phases, and SUM can stop at breakpoints for manual work. The most important line in that roadmap is not a step boundary, though. It is the moment downtime starts: before it, business users keep working in the system; after it, they are locked out until the run and the follow-up checks are done.
- UptimeExtractionSUM unpacks the archives, reads stack.xml and prepares its directory
- UptimeConfigurationMode, processes, passwords and options are chosen
- UptimeChecksSpace, versions and prerequisites; SI-Check runs at the start
- UptimePreprocessingShadow instance built; new repository imported and activated; SPDD adjustment
- DowntimeExecutionSwitch to the new repository, main import, table conversion, data conversion (and DMO migration)
- Downtime / afterPostprocessingCleanup, logs, follow-up programs; then SPAU and application follow-up
The shadow system
Most upgrade work does not need to wait for downtime. SUM uses the system switch approach: during uptime it installs a shadow instance that runs with the target release kernel and works on a shadow repository, a copy of the repository tables created under alternative names. The shadow instance has no access to application data. In it, SUM imports the new repository, adjusts and activates dictionary objects and distributes the changes. Activation alone can take hours, which is exactly why it is done while users still work.
The shadow system has a price. It needs extra memory for the additional instance, extra database space for the shadow tables, and it imposes a freeze: once SUM starts building the shadow repository, ABAP development and transports into the system are no longer allowed, because changes in the original repository would be lost. Dictionary modifications are adjusted with transaction SPDD in the shadow instance before activation; skipping that step means modified dictionary objects are overwritten by the SAP standard version. Repository objects other than dictionary objects are adjusted after the run with SPAU and SPAU_ENH.
Preconfiguration modes
| Mode | What it does | When to use |
|---|---|---|
| Single system | No shadow instance in uptime; most work happens in downtime. Since SUM 2.0 SP 07 only for support package or stack updates, not upgrades or conversions, and not with DMO. | Small maintenance where a longer downtime is acceptable |
| Standard | Shadow system in uptime; modification adjustment before downtime; downtime largely independent of the number of support packages, languages and add-ons | Most upgrades and conversions |
| Downtime-optimized | Extension of standard with more parallel processes; can be combined with techniques such as downtime-optimized DMO or nZDM | Large systems with tight windows, after the standard path is understood |
SUM preconfiguration modes. Names and options vary slightly between SUM versions; check the SUM guide for your support package.
What would you do?
During Contoso's second mock conversion, SUM is in Preprocessing on a copy of EP1. A developer asks Sam to import an urgent transport into the copy so the mock reflects last week's production fix. What should Sam say?
- Six roadmap steps: Extraction, Configuration, Checks, Preprocessing, Execution, Postprocessing; downtime begins at Execution.
- The shadow instance builds and activates the target repository during uptime, without access to application data.
- The shadow costs memory and space and freezes development and transports once it starts.
- SPDD happens in the shadow before activation; SPAU and SPAU_ENH come after the run.
- SUM re-runs the SI-Check at the start and before downtime; return code 8 or higher stops the run before downtime.
Check your understanding · not graded
Lesson check
1. Why does SUM build a shadow repository during uptime?
2. In which roadmap step does business downtime begin?
3. When are modified dictionary objects adjusted with SPDD?
4. Just before downtime, which SI-Check result stops SUM?