Process Flow on Starting & Stop SAP Instance

Flow and processes on starting up SAP

Starting an SAP System is performed in a number of steps and is the task of the
operating system user adm.

Start the database:
•The underlying element of the entire SAP system is the database. Before the
SAP instances are started, this must have operational status. The database is
therefore always started as the first step.

Start the central instance:
•Next, the operating system collector SAPOSCOL is started, this program collects data
about operating system resources and makes this data available through the
shared memory of all SAP instances.

Follow by starting up message server and the dispatcher and its work processes.

The dispatcher also starts the Internet Communication manager (ICM) and the
SAP Web AS Java (if it is installed).

When the instances are started, SAP Service reads which processes (message
server, dispatcher) are to be started from the instance-specific start profile. These profiles are read by the dispatcher, which starts the work processes and creates the instance-specific configuration.

After the instance has been successfully started, all work processes connect to
the database.

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How to Start and Stop SAP Instance

Proper way to Stop SAP instance and Oracle db.
1. Stop SAP Instance
2. Stop Oracle DB

To Start - reverse way
1. Start listener
2. Start Oracle db and start SAP instance


Command to Start and Stop SAP in hp-ux/ unix / linux
---------------------------------------------------------------
- Login as adm
- "stopsap"

While starting
- Login as ora
- "lsnrctl start"
- "su - adm" (login as adm)
- "startsap"


Alternative command to Start and Stop SAP instance and Oracle database in Unix
"stopsap all" - stop r3 and database.
"stopsap db" - stop only the database.
"stopsap r3" - stop r3 instance only.

"startsap all" - starts r3 and database.
"startsap db" - starts only the database.
"startsap r3" - starts r3 and assumes that the database is already started.

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Basic Spool & Printing Concept

Spool request is the SAP naming convention for output job or print job, but in SAP terms a spool request is made up of the spool request record (administrative information to manage the print jobs), the data that are sent to the printing devices, and the actual output request. A spool request is not necessarily meant just for printing, it also can be generated for other communication or archiving devices.

Output requests are the component of the spool request which actually formats the output data and sends it to the host spool system to be printed. You can submit multiple output requests for a single spool request. Eg you can have a spool request printed on different printers or reprint a request if it could not be printed successfully the first time.

Access methods are how the SAP spool work process communicates with the host spool system
SAP scripts is SAP own text editor which is used for creating and formatting documentation in SAP, such as online help, forms, implementation guide texts, mail message and so on.

List Output is a generic name for the output that is generated by ABAP reports and that is not formatted using SAP Scripts. The spool system handles both types of output that generated by SAP Scripts text editor and the results of an ABAP report.

Forms define the page layout for texts, report list, and the like that are specially prepared for display or for printing.

Layout sets are maps of output pages that specify where the text is placed on the page what its attributes are.

Temse stands for the temporary sequential object database, which is a special place where the SAP system stores the spool request data and other SAP objects such as the background job logs.

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SAP Printing System

SAP provides its own spooling and printing system within the SAP applications to enable a uniform interface for all printing functions, independently of the system platforms supporting both printing devices and application services. This is one of the features of the traditional open client/server architecture of the SAP Basis system.

There is at least one running spool work process when a SAP application server is configured for a spool server. This does not mean that the application server is not running other types of SAP services. These servers can be small, dedicated workstations with a high speed network connection to the other servers, which are used for connecting and configuring the host printers used by the SAP system.




Printers or other output devices defined in SAP spool system have a primary spool server designated; that is a server with one or more spool work processes running on it. This server is in charge of processing spool requests for those printers and devices. If the primary spool server becomes unavailable, it is possible to specify an alternate spool server in order to process the spool request from those printers and devices.

The host spool system is the ultimate component in charge of sending the print job to the physical printer. This is basically how the printing system works in SAP WAS.

***A spool request is not necessarily meant just for printing. It can also be generated for other communication or archiving devices.

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What are the 3 Layer in SAP R/3 architecture?

They are:-

• Presentation Layer
• Application Layer
• Database Layer
  
  

Presentation Layer is the system with GUI where the enduser works and directly
collect the requirment from end users to be process to on the next layer(Apps Layer & DB Layer)

The Application Layer of an R/3 System is made up of the application servers and the message server. Application server is where the dispatcher distribute the work load to the different work processes(like Dailog workprocess, Background workprocess, Spool workprocess, Update Workprocess, and Enque workprocess)and makes the job done.

Database Layer is where it contains three buffer( Database buffer,SQL buffer and Redolog buffer )and as Actual database where the commited data is stored.

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