Instance
Quick answer
Basis administrators start, stop, monitor and tune instances, adjusting work-process counts and memory to the workload.
Key takeaways
- An instance is one running copy of the SAP application-server software: its dispatcher, its work processes (dialog, background…
- You scale an SAP system horizontally by adding application-server instances, distributing user load across them via the message…
- A central services / ASCS instance provides message and enqueue services.
- Watch out: Confusing instance, system and client.
What an instance is
An instance is one running copy of the SAP application-server software: its dispatcher, its work processes (dialog, background, update, enqueue, spool) and its memory buffers. A system can have one instance or many, all connected to the same database.
Central and dialog instances
- A central services / ASCS instance provides message and enqueue services.
- The primary application server instance.
- Additional application server instances for more capacity.
Instances and scaling
You scale an SAP system horizontally by adding application-server instances, distributing user load across them via the message server. Each instance adds work processes and memory, increasing how many users and jobs the system can handle, while all share one database.
Operating instances
Basis administrators start, stop, monitor and tune instances, adjusting work-process counts and memory to the workload. Instance configuration (the ratio of dialog to background processes, for example) directly affects performance.
Common pitfalls
- Confusing instance, system and client.
- Poor work-process ratios per instance.
- Assuming a single instance in production designs.
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Check your understanding
Which statement is true of Instance?
- A. A system can have one instance or many, all connected to the same database.
- B. These SQL examples show querying SAP data effectively, whether Open SQL in ABAP or native HANA SQL, with an…
- C. PFCG is the SAP transaction code for Role Maintenance (Profile Generator) (Basis/Security).
Show answer
A. A system can have one instance or many, all connected to the same database.
Covered in the “What an instance is” section of this lesson.
Which of these also applies to Instance?
- A. You scale an SAP system horizontally by adding application-server instances, distributing user load across…
- B. Frontend app without backend authorization (or vice versa).
- C. Learning features, not the end-to-end process.
Show answer
A. You scale an SAP system horizontally by adding application-server instances, distributing user load across…
Covered in the “Instances and scaling” section of this lesson.
Which part of the Learn SAP curriculum covers Instance?
- A. SAP administration
- B. SAP tables
- C. SAP architecture
Show answer
C. SAP architecture
This lesson sits in the SAP architecture section of the Learn SAP course.