User Guide

SAP AG November 2002

Variables

The following table shows which variables are used in the explanation of the Directory

Structure of the Database System for SAP Systems [Page 67].

Version number of the SAP DB software

<database_name>

Name of database instance

<independent_data_path>

Data path independent of the version (IndepDataPath)

<independent_program_path>

Program path independent of the version

(IndepProgPath)

<dependent_path>

Data path dependent on the version (InstRoot directory).

This path specification must be explicit.

Distribution of the SAP DB Directories on the Hard

Disk

The ideal directory structure of the database system for SAP Systems [Page 67] depends on

the hardware configuration. There is no single solution or definition for the distribution of the

files of an SAP DB database instance [Page 132].

When attempting to find the optimum data distribution for your database environment in a

production system, bear in mind the information in the following sections:

• Security Requirements [Page

75]

• Performance Requirements [Page

76]

• Example Configuration [Page

77]

• Various Database Systems [Page

77]

• SAP DB Directories [Page

70]

Security Requirements

Using the appropriate hardware, operating system, or database features can improve the

availability [Page 38] of a database instance [Page 132].

• Log volumes [Page

144]

In the production system, the log area [Page 142] should always be mirrored for

security.

Ideally, you should use hardware-based options for this mirroring.

However, you can also use the DUAL log mode [Page 143] of the SAP DB database

system.

You should not use RAID-5 configurations for the log volumes. RAID-5 systems do

not allow full mirroring. Because the database instance writes log entries sequentially,

this can lead to a loss in performance.

In a production system, logging should never be deactivated, even if you use RAID

systems.