Computer Associates BABWBR1151S38 Implementation Guide - Page 24

Data Transfer Requirements Backup Scope You might segment your data for backup purposes in any of the following ways: ■ Business function (such as accounting, engineering, personnel management, sales, and shipping) ■ Geographical location (such California development lab, St. Louis distribution center, New York business office, Miami business office, Tokyo business office, and Paris distribution center) ■ Network location (such as NA005, NA002, NA003, JP001, and EU001) Your segmentation scheme should, however, group the data into reasonably contiguous backup sources, so that the speed you gain is not lost in lengthy searches and additional network traffic. After you have segmented your data, you can further reduce the required data transfer rate by reducing the scope of some backups. Typically, a relatively small percentage of your data changes from day to day. While these changes need to be saved, a full backup is usually unnecessary. Example: Backup Scope If you try to back up everything daily and only 10% of the data changes in the course of a day, you are spending 90% of your limited backup time storing data that is already backed up. When you include media consumption and wear and tear on your backup devices, this can be an expensive proposition. You should consider backing up everything weekly, after 50% or more of your data has changed. You could then use the longer, weekend backup period for your longest storage operation. On a daily basis, you could back up the changes only. This would let you stay within the short, nightly backup window and would economize on media. CA ARCserve Backup provides options for you to address this issue with the following types of backups. ■ Full backups--stores everything, regardless of when the data last changed. ■ Differential backups--stores files that have changed since the last full backup. ■ Incremental backups--stores files that have changed since the last full or incremental backup. ■ Synthetic full backups--for r16 or higher Windows Client Agents, synthesizes a previous full backup session and all incremental sessions to a full session without the need for previous incremental sessions. 24 Implementation Guide