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Chapter 3: Backup and RecoveryPerformanceThe most important performance target is the time required to restore the database. Thisdetermines how long the R/3 system will be down and not available for use. With R/3down, certain company operations may not occur.Backup performance is important, especially if the system is global or used 24 hours a day.When doing a backup, it is important to minimize the impact on users. The key is to reducebackup time, which in turn reduces the impact on the users.To increase performance:1. Identify the bottleneck or device that is limiting the throughput.2. Eliminate the bottleneck.Repeat steps 1 and 2 until the performance is adequate or the additional cost is no longerjustified.This iterative process is subject to cost considerations. Additional performance can alwaysbe purchased, which is almost always a business cost justification exercise.All of the backup performance items that follow also apply to restoring the database.There are three major variables that affect performance: Database sizeThe larger the database, the longer it will take to back up. Backup windowThe backup window is the time allocated for you to take the regular backups of thesystem. This window is driven by the need to minimize the impact on users. An online backupThe backup window for this backup type is defined as the time when there are thefewest users on the system and is usually done early in the morning. An offline backupThe backup window for this backup type is defined by when and for how long R/3can be brought down and is usually done during the weekend. Hardware throughputThis variable limits how fast the backup can run and is defined by the slowest link in thebackup chain such as: Database drive array I/O channel that is used Tape drive3–20Release 4.6A/B