SAP Start-up procedure for ABAP system

The SAP System contains of Database Instance,
Central Services (Message server, Enqueue),
finally the multiple Dialog Instances (ABAP Work Process).

Sequence of startup steps:

- Login to SAP with the <sid>adm user To startup the SAP system

• The <sid>adm user belongs to the Unix Group called sapsys on the Unix flavers .
• The <sid>adm belongs to the Windows Group called SAP_<sid>_GlobalAdmin and Administrators Group.

1. First the database instance will start
2. If Central Services has been setup, this has to be started next. This means that the Enqueue Service     and the Message service should be started.
3. An independent program called SAP OS Collector (saposcol) is started along with the remaining ABAP work processes in the Central Instance.The dispatcher work process is started after that
4. Saposcol collects statistical data from the operating system such as CPU and Memory usage               parameters
5. Then the individual dialog instances can be started. There is no dependency between the dialog           instances

Role of SAP profiles in startup:

Each SAP instance , whether it is application instance or a dialog instance has three profiles.

START PROFILE        ( START<Instance><Instance Number>_<Host name> )
DEFAULT PROFILE      (DEFAULT.PFL)
INSTANCE PROFILE     (SID<Instance><Instance Number>_<Host name> )

• The start profile is read by the sapstartsrv process and inputs are provided on the SAP system ID and number, as well the physical file paths of the sap executables for starting message service and enqueue service.
• Once the dispatcher work process is started, the Default Profile file is read. This file provides the necessary information to the dispatcher on the memory and sap application performance settings required to run the instance.
• The instance profile is the last file to be read. Any settings in the instance profile file will override the settings in the default profile file.