Preparing the OS for an Installation of an SAP System

You should use the prerequisite checker tool to check the hardware and software requirements for your operating system and the SAP instances.

The prerequisite checker tool provides information about the requirements that you need to meet before you start the installation; for example, it checks the requirements for the various installation services. At the completion of the prerequisite check, a report displays the result of each check, the severity of issues, and links to more detailed information. The following figure Results of Prerequisite Check - Page / Swap shows a sample of the results report.

When you install an SAP system, you must first prepare the operating system.

Set the paging/swap file size according to the recommendations of the installation guides and the Prerequisite Check tool.

Domain or Local Installation

You can decide whether you want to install your SAP system on the hosts locally or using a Windows domain. SAP recommends that you install your SAP system using a domain.

For a domain installation, SAP recommends that all SAP systems and database hosts are members of a single Windows domain. This recommendation is valid for all SAP system setups, whether standalone central systems or distributed systems. In the single Windows domain model, the SAP system and the user accounts are included in a single Windows domain.

If you want to transport objects between different SAP systems using the Change and Transport System (CTS), ensure that all SAP systems are either members of a single domain or members of different domains with a trust relationship established between them. Only SAP application and SAP database servers, and no other software, should be members of the domains.

For a local installation, the installation user needs local administration rights. For a domain installation, the installation user needs domain administration rights.

For a local installation, you need an installation user who is a member of the local administrators group.

When you perform a domain installation, you must be a domain administrator. However, you can perform a domain installation even with local administration rights. In this case, the domain administrator has to make additional preparations. Refer to the installation guide for a detailed description of these preparations.

Transport Host on Windows

The transport host has a directory structure that the SAP transport system uses to store transport and metadata. The SAP transport system stores the change information such as ABAP programs, data of dictionary data, customizing data, and SAP Support Packages from SAP Support Portal, in files that are located in transport directory structure. If you do not want to use the directory structure of the SAP system that you are going to install, prepare a directory structure on the transport host.

Prepare one host for the role of a transport host. This host controls the import or export of files between the current SAP system and other SAP systems, such as a test or production system.

The global transport directory \usr\sap\<name of the transport directory> is used by the Change and Transport System (CTS). The CTS helps you to organize development projects in the ABAP Workbench and in customizing, and then transport the changes between the SAP systems in your SAP system landscape.

In the case that the Primary Application Server does not reside on the server that you want to use as the transport host, you must create the transport directory structure (including shares), manually.

1. To prepare the transport directory:

   • If you install the first SAP system of the SAP system landscape, for example, the development system, you can use the installed file system structure on the host of the PAS instance of this SAP system.
   • If the directory structure already exists, set up its security to allow the new SAP system to write into it.
   • If the directory structure does not exist, create the core directory structure and a share to export it for other hosts as well as setting the security on it.

2. On the transport host, create the directory \usr\sap\<name of the transport directory>

3. Grant full control permission of the directory to <SID>adm and additionally, on Windows, to SAPService<SID>.

4. Share the \usr\sap directory on the transport host as sapmnt. This enables SAPinst to address the transport directory in the standard way as

   \\SAPTRANSHOST\sapmnt\<name of the transport directory>.

As of Release SAP NetWeaver 7.0, the structure of the Windows file system for the SAP system kernel has undergone minor changes.

Before you install an SAP system on Windows, perform the tasks in the following checklist.

For some Linux/UNIX operating system (OS) and database system combinations, you must modify the Linux/UNIX kernel parameters. You can find the information corresponding to your operating system in the installation guide. If you do not want SAPinst to create operating system users, groups, and services, you can create them before the installation.

Network Information Services (NIS)

If you use NIS, distribute users over the network.

SAPinst checks all the required users, groups, and services on the local machine. If you manage users, groups, and services across the network in your company, create the user and group NIS entries before running SAPinst.

SAPinst checks whether the required services are available on the host and creates them if necessary. See the log notifications about the service entries and adapt the network-wide NIS entries accordingly. SAPinst checks the NIS users, groups, and services using NIS commands. However, SAPinst does not change NIS configurations.

During the installation process, set up the file systems and raw devices for the SAP system and database. Manually set up the file systems as shown in the previous figure. SAPinst does the rest of the set up during the installation process. If you do not set up any file system on your installation host, SAPinst creates all directories in the root directory (/). SAPinst prompts you only for directory <sapmnt> during the installation.

The file system starting from ASCS<nn> is from the Central Services instance of an AS ABAP-based SAP system.

For the space required by various file systems, refer to the installation guide. The processes of creating and mounting file systems and creating raw devices for an SAP system and for different databases are described in the installation guide.

In your SAP system landscape, a global transport directory is required for all SAP systems. If a global transport directory already exists, confirm that it is exported on the global transport directory host and mount it on the SAP system installation host.

If a global transport directory does not exist, proceed as follows:

1. Create the transport directory (either on the central instance host or a file server).
2. Export the transport directory on the global transport directory host.
3. If you did not create the transport directory on your SAP instance installation host, mount it there.

The tasks that you must perform before you install and SAP system on UNIX are listed in the following table.