SAP Instance profiles

 SAP profiles are critical for the operation and performance of an SAP system. They define various parameters that control the behavior of the SAP instances, the kernel, and the entire system. Understanding and managing these profiles is a core responsibility of an SAP Basis administrator.

The primary transactions for managing profiles are RZ10 (for maintaining profile files) and RZ11 (for displaying and dynamically changing profile parameters).

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Understanding SAP Profiles

An SAP system typically uses three types of profiles:

1. Start Profile (START_DVEBMGS<InstNo>_<Hostname>):

   • Defines how an SAP instance starts.
   • Specifies which executables (sapstartsrv, disp+work, msg_server, enque_server) should be started, in what order, and with what parameters.
   • Also points to the instance profile that the instance should use.
   • Usually one start profile per SAP instance.

2. Instance Profile (e.g., <SID>DVEBMGS<InstNo><Hostname>):

   • Most Important Profile.
   • Contains parameters specific to an individual SAP application server instance.
   • Defines the number and type of work processes (dialog, background, update, spool), memory parameters, buffering settings, trace levels, and many other operational parameters.
   • There is one instance profile for each SAP instance.

3. Default Profile (DEFAULT.PFL):

   • Contains parameters that apply to all SAP instances within a single SAP system.
   • Parameters defined here are inherited by all instance profiles unless explicitly overridden in an instance profile.
   • Typically contains parameters like message server port, database connection parameters, and other global settings.
   • There is only one default profile per SAP system.

Location of Profile Files:

SAP profiles are physically stored on the operating system level, typically in the instance's profile directory:

• Unix/Linux: /sapmnt/<SID>/profile
• Windows: C:\usr\sap\<SID>\SYS\profile

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Managing Profiles with RZ10: Creation and Maintenance

RZ10 is the central transaction for managing profile files. It provides a structured way to create, modify, activate, and manage versions of SAP profiles.

Key Features of RZ10:

• Edit Profile: Modify existing profile parameters.
• Create Profile: Create new start, instance, or default profiles.
• Import Profile: Import profile from a different system or a local file.
• Activate Profile: After changes, activate the profile to make it the active version.
• Version Management: RZ10 automatically manages profile versions, allowing you to revert to previous versions if needed.
• Consistency Check: Performs a syntax check and consistency check of parameters before activating.

Steps to Create/Modify a Profile (Instance Profile Example):

1. Execute RZ10.
2. Profile Selection:
   • Enter the full name of the profile (e.g., PRD_DVEBMGS00_saphost).
   • Alternatively, use the F4 help to select from existing profiles.
   • If creating a new profile, just type the desired name.
   • Select the Profile Type (Default, Instance, Start).
3. Edit Mode:
   • Click on "Extended maintenance" (recommended for detailed control).
   • Click "Change" to enter edit mode.
4. Parameter Maintenance:
   • You'll see a list of parameters. To add a new parameter, click "Parameter" -> "Create" or use the "Create Parameter" button.
   • Parameter Name: Enter the parameter (e.g., rdisp/max_wprun_time).
   • Parameter Value: Enter the desired value (e.g., 600).
   • Description: (Optional but recommended) Add a brief description.
   • Saving Changes: After adding/modifying parameters, click the "Copy" or "Enter" button to confirm the parameter change within the profile editor.
5. Check and Save:
   • Click the "Check" button (looks like a clipboard with a green checkmark) to perform a syntax and consistency check. CRITICAL! Address any errors or warnings.
   • Click the "Profile" -> "Save" (or the save icon). This saves the profile to the database.
6. Activate Profile:
   • After saving, you'll be prompted to "Activate profile." Select "Yes."
   • Activating a profile updates the physical profile file on the OS level in the /sapmnt/<SID>/profile directory and sets it as the active version.
   • Impact: Most profile changes (especially for instance profiles) require an SAP instance restart to take effect. RZ10 will not automatically restart the instance.

Important Considerations for RZ10:

• Test Environment First: NEVER make profile changes directly in a production system without thoroughly testing them in a development or quality assurance environment.
• Backup: Before making major changes, take a backup of the existing profile files from the OS level. RZ10 also maintains versions, providing a safety net.
• Documentation: Document all changes made, including the parameter name, old value, new value, reason for change, and who made the change.
• Parameter Dependencies: Some parameters have dependencies on others (e.g., memory parameters). Changing one might require adjusting others.
• SAP Notes: Always consult relevant SAP Notes for recommended parameter values for specific scenarios (e.g., HANA migrations, high availability, performance tuning).
• Comments: You can add comments to profile parameters directly in the DEFAULT.PFL or instance profiles at the OS level by starting the line with #. RZ10 allows adding a "description" but not inline comments.

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Displaying and Dynamic Changes with RZ11

RZ11 is used to display the current values of profile parameters and, for some parameters, to change them dynamically without requiring an instance restart.

Key Features of RZ11:

• Display Parameter Values: Shows the current, default, and dynamically changeable values of parameters.
• Dynamic Change: For certain parameters, you can change their values at runtime.
• Documentation: Provides detailed documentation for each parameter, explaining its purpose, valid values, and restart requirements.

Steps to Display/Change Parameters with RZ11:

1. Execute RZ11.
2. Parameter Name: Enter the exact parameter name (e.g., rdisp/max_wprun_time). You can use wildcards (rdisp/*) to search.
3. Display: Click "Display."
4. Parameter Details:
   • You'll see information like:
     • Parameter Name:
     • Current Value: The value currently active in the running instance.
     • Default Value: The SAP-defined default value.
     • Profile Value: The value set in the active profile file (from RZ10).
     • Dynamic Switch: Indicates if the parameter can be changed dynamically (e.g., X for Yes, blank for No).
   • Documentation: Click on the "Documentation" button (looks like an 'i' in a circle) to read detailed SAP documentation for the parameter. This is CRITICAL for understanding its impact.
5. Change Value (If Dynamic Switch is 'X'):
   • Click on "Change Value" (looks like a pencil).
   • Enter the "New value" and confirm.
   • Impact: The change takes effect immediately for the running instance. However, this change is not persistent across instance restarts. To make the change permanent, you must also update the parameter in RZ10 and activate the profile.

Important Considerations for RZ11:

• Dynamic vs. Persistent: Remember, RZ11 changes are dynamic (runtime) only. For persistent changes, always use RZ10 and restart the instance.
• System Impact: Even dynamic changes can have significant impact. Always understand the parameter's documentation before changing it.
• Troubleshooting: RZ11 is invaluable for quickly checking currently active parameter values during troubleshooting.

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Critical Parameters and Common Scenarios

While there are thousands of parameters, some are frequently adjusted:

• Work Processes:
  • rdisp/wp_no_dia: Number of dialog work processes.
  • rdisp/wp_no_btc: Number of background work processes.
  • rdisp/wp_no_upd: Number of update work processes.
  • rdisp/wp_no_enq: Number of enqueue work processes (usually 1, only on enqueue server).
  • rdisp/wp_no_spo: Number of spool work processes.
  • Scenario: Performance bottlenecks, long-running jobs, update termination.
• Memory Parameters:
  • abap/heap_area_dia: Heap memory for dialog WPs.
  • abap/heap_area_nondia: Heap memory for non-dialog WPs.
  • em/initial_size_MB: Extended Memory size.
  • ztta/roll_area: Roll Area size.
  • rdisp/ROLL_MAXFS: Max Roll File System size.
  • rdisp/PG_MAXFS: Max Paging File System size.
  • Scenario: TSV_TNEW_PAGE_ALLOC_FAILED dumps, PXA_NO_SHARED_MEMORY errors, system performance issues related to memory.
• Timeouts:
  • rdisp/max_wprun_time: Max runtime for dialog work processes.
  • rdisp/gui_auto_logout: Automatic GUI logout time.
  • rdisp/max_alt_modes: Max number of GUI sessions.
  • Scenario: Users getting timed out, long-running reports being cancelled.
• Buffering:
  • rsdb/ntab/entrycount: Number of entries in Nametab buffer.
  • sap/bufdir_entries: Directory entries for Program buffer.
  • rsau/local_buffers: Security Audit Log buffer size.
  • Scenario: Poor application performance due to excessive database reads.
• Security:
  • login/no_automatic_user_sapstar: Prevents automatic login with SAP* if user exists.
  • login/min_password_length: Minimum password length.
  • Scenario: Compliance, security audits.

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Profile Management Best Practices:

• Change Management: Integrate profile changes into your IT change management process. All changes should be approved, documented, and tested.
• Versioning: Always activate the profile in RZ10 after changes. RZ10 automatically handles versioning, allowing you to compare and revert to older versions.
• Central Instance vs. Dialog Instance: Pay attention to which parameters apply to the Central Instance (which runs message server and enqueue server) vs. Dialog Instances. Some parameters are only relevant for one type.
• OS-level vs. RZ10: While you can edit profile files directly at the OS level using a text editor, it's highly discouraged for active profiles. RZ10 provides consistency checks, versioning, and ensures the profile is correctly saved in the database. Only use OS-level editing for troubleshooting or for non-active backup copies.
• Consistency Checks: Always use the "Check" function in RZ10 before saving and activating. Address all warnings and errors.
• Restart Requirements: Be aware that most significant changes require an SAP instance restart. Plan downtime accordingly.
• Monitoring: After any profile change and restart, closely monitor the system using transactions like ST02 (Buffer Monitor), SM50 (Work Process Overview), ST04 (DB Performance), ST06 (OS Monitor), and SM21 (System Log) to ensure the changes have the desired effect and don't introduce new issues.

By following these guidelines, Basis administrators can effectively manage SAP profiles, optimize system performance, and maintain a stable SAP environment.