Computer Associates ARB6002700WF0. ..... Administration Guide - Page 48

Defining Data-transfer Requirements 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. Reducing the Scope of Some Backups 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. For example, if you try to back up everything daily and only 10% of the data changes in the course of a day, you are spending 95% 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 back up window and would economize on media. BrightStor ARCserve Backup addresses 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 backup of any type. Getting the right mix of full and partial backup operations is something of a balancing act. Ideally, you want each version of each piece of data backed up once. You want to minimize unnecessary duplication that consumes media and time. Therefore, you should keep the following considerations in mind: 2-10 Administrator Guide