SAP Standard Filesystem Hierarchy.

SAP Standard Filesystem Hierarchy

usr/sap 
/usr/sap/ccms
/usr/sap/SID
/usr/sap/SID/DVEBMGSnn                contain SAP instance specific directories data, log, and work..
/usr/sap/SID/DVEBMGSnn/work
/usr/sap/SID/SYS                               contain profile, global, and exe directory.
/usr/sap/SID/SYS/exe
/usr/sap/SID/SYS/global    -->       /sapmnt/SID/global.
/usr/sap/SID/SYS/profile    -->      /sapmnt/SID/profile.
/usr/sap/trans                                  Transport directory.
/usr/sap/trans/bin                            TPPARAM file (global transport parameter).
/usr/sap/trans/buffer                        Special buffer with the SID of every system in the transport.
 
group (including control information)
/usr/sap/trans/cofiles                        Transport request control file.
/usr/sap/trans/data                            Transport request data file.
/usr/sap/trans/EPS
/usr/sap/trans/EPS/in
/usr/sap/trans/log                              Transport logs, trace and statistic file.
/usr/sap/trans/tmp                             Temporary directory.

                                                 //sapmnt
                                                       |
                                                    SID
                                                       |
                                           +-------+-------+
                                                     | | |
                                             exe global profile
/sapmnt       directory structure for sharing common files to all system belonging into the same group.
/sapmnt/SID              shared directory or link to directory /usr/sap/SID/SYS
/sapmnt/SID/exe        SAP executable application directory.
/sapmnt/SID/global    SAP central system log.
/sapmnt/SID/profile    SAP instance profile.



 

Standard Users in SAP.

Users

SAP*

SAP* is the super user of SAP system and used for doing client copy. SAP* is the only user in the SAP System that does not require a user master record, but that is instead defined in the system code itself. SAP* has by default the password 'pass', as well as unlimited system access authorizations. When you install your SAP System, a user master record is defined for SAP* with the initial password as the master password (set during installation) in clients 000 and 001. The presence of a SAP* user master record deactivates the special properties of SAP* and standard password 'pass'. It has only the password and the authorizations that are specified for it in the user master record.
When temporary license expires only SAP* user is allowed to login to client 000 to install permanent
license.

DDIC
 
It is the maintenance user for ABAP Dictionary and software logistics. It is used for any upgrade or installation type of work like,
1. TMS Configuration,
2. Applying Support Packages,
3. Applying Add-ons,
4. Implementing SAP Notes etc.

• Best practice is not to use DDIC user but create a new user by copying from DDIC.
• DDIC is the only user that is allowed to log on to the SAP System during an upgrade.
• DDIC is hard coded to do some things other IDs cannot and restricted from doing some things that other IDs can.

EARLYWATCH
 
The SAP EarlyWatch service uses this user. This user should only be used for EarlyWatch functions like monitoring and performance analysis.
Default users in each clients,

Client 000
Username: SAP* --> short for SAP Star
Password:
Username: DDIC --> copy of SAP*, short for Data Dictionary
Password:

Client 001
Since Client 001 is a copy of Client 000, it has the same users and passwords as in Client 000.

Client 066
Username: EARLYWATCH
Password: support

New Client
Username: SAP*
Password: pass


 

What is Logical System in SAP?

Logical System

When data is distributed between different systems, each system within a network has to be clearly identifiable. The "logical system" deals with this issue.

A logical system is an application system in which the applications work together on a common database. In SAP terms, the logical system is a client.

Since the logical system name is used to identify a system uniquely within the network, two systems cannot have the same name if they are connected to each other as BW systems or as source systems, or if there are plans to connect them in any way. 

The logical system’s naming convention is CLNT such as SDKCLNT100

What is Client in SAP

Client
Introduction
 
A client is a self-contained business entity or unit within each SAP system with independent information and data. The main objective of the client is to keep the business data isolated so that other clients cannot access or change them.

The SAP client concept allows an organization to split a system into logical subunits. Clients may operate as separate business units, where all data is stored in a common database. Client specific data includes User Master Records (including authorizations and user groups), data customization and application/business data

• Client-specific data is data affecting only one client, such as user master and application data.
• Cross-client data is data affecting the whole system environment, such as cross-client Customizing data and all Repository objects.

SAP supports up to 1000 clients starting from 000 to 999.

SAP Standard Clients 

SAP R3 comes with 3 inbuilt standard clients,

000 – Master Client aka Reference Client

Client 000 contains a simple organizational structure of a test company and includes parameters for all applications, standard settings, and configurations for the control of standard transactions and
examples to be used in many different profiles of the business applications. It contains clien independent settings.
 

001 – Copy of Client 000
This client is a copy of the 000 client including the test company. This client's settings are  clientindependent if it is configured or customized. People normally use 001 client to create a new client.

066 – EarlyWatch Client (SAP Support)
The SAP EarlyWatch Alert is a diagnosis service, for solution monitoring of SAP and non-SAP systems in the SAP Solution Manager. Alert may contain Performance issue, average response time, current system load, Database administration etc.

Golden Client
Golden Client is the client where all the developments i.e. changes and modifications like configuration settings and cross-client customizations are made and tested, which are later transported to the Quality and Production clients.

A Golden client is configured to automatically record all changes and store in change requests.

SAP Work Process and Types

Work Processes

The SAP work process is a component of the application server that executes an ABAP application.
SAP work processes are started as operating system processes, each with its own process ID (PID).
The majority of the processing of the application is performed by the SAP work processes.

D – Dialog
V – Update
E – Enqueue
B – Background
M – Message Server
S – Spool
G – Gateway Server

Dialogue

It is the only work process which communicates interactively with the users.
There should be at least 2 Dialogue work process per instance. Dialogue work process initiates Update, Background and Spool.The dialog work processes are in charge of the interactive tasks of the R/3 system. A dialog work process performs the dispatcher in the request queues after user input are assigned to the next free work process. The dialog work processes execute just one single dialog step at a time and become immediately free for the next user request (dialog step), which is assigned by the dispatcher. This is called work process multiplexing. This means that the dialog work processes can be constantly switching between different user sessions. This type of processing allows a great deal of resource distribution; otherwise the system would need as many dialog work processes as the number of expected interactive users.  It works exactly the same as multiuser operating systems. Depending on the type of business transactions the users are working on, a dialog work process can support from 5 to more than 10 simultaneous users each. This means that 10 dialog work processescould theoretically support approximately 100 users. However, this is just a rule of thumb. Tuning this parameter means that if users have to wait long to get a free work process, you should increase the parameter.

Update

It is used to update the transactions in the database. It is initiated by Dialogue process. There should be at least 1 Update work process in the entire system. It is also recommended to have an update process for every 5 Dialogue.

Enqueue

It is used to provide locks for the records that are going to be updated. It ensures consistency for updates. There will be only 1 Enqueue configured in the system during the installation. It is possible to have more than one enqueue provided they are installed or configured on the central instance.

Background

The tasks which are expensive or time consuming are scheduled to run in the background mode noninteractively. There should be at least 2 background work process in the system

Message

There should be only 1 message server in me entire R/3 system. It is used to manage all the dispatchers. It is used to load balance the requests to identity the least loaded dispatcher. It is also used to provide locks to the request that are coming from Dialogue instances.
Gateway

It is used to provide a means of communication with SAP and NON-SAP systems. There will be only 1 gateway for each instance.

Spool

It is used to print the documents to a printer or output to a fax machine etc. There should be at least 1 Spool process in the entire system. It is also possible to configure more spool process depending on the print/spool volume.

Sybase sybctrl: connect to DB fails error

Symptom

On Linux / Unix sybctrl cannot connect to database.
The error message is similar to:
Could not load SYB library libsybdrvodb.so. No database connection possible.
Other Terms

sybctrl sybxctrl
 
Reason and Prerequisites

If sybctrl has the s-bit set and runs as a setuid program, LD_LIBRARY_PATH will be ignored by operation system for security reasons.
Shared libraries will not to be found and load of odbc driver will fail.
 
Solution

Use sybxctrl which is a copy of sybctrl without the s-bit set.

sybxctrl will be created if the database is stopped using stopsap script or stopdb script.

Otherwise create sybxctrl by executing as user adm:
 
cd /usr/sap//SYS/exe/run
 
cp sybctrl sybxctrl




More details refere Snote : 2719763