If the database is very large, it might be impractical to fully back up the database daily. You might choose to back up the database file every other day, or even once a week. Instead of frequent full backups, consider performing daily incremental backups or, if you have after-imaging enabled, only backing up the after-image files.

You can perform daily incremental backups. Incremental backups only back up the blocks that have changed since the previous backup. You can specify an overlap factor to build redundancy into each backup and help protect the database. However, you should also perform a full backup at least once a week to limit the amount of backup media used for incremental backups and to ease data recovery.

If you enable after-imaging, back up the after-image files every time you perform a backup. Immediately after performing a full or incremental backup, start a new after-image file. When you back up AI files, you back up whole transactions, but incremental backups back up just the blocks that have changed. As a result, AI file backups can use more space than incremental backups.

If you make many database updates and you are on a weekly full backup schedule, it is possible that the after-image files will grow very large during the week. If so, backup and empty the AI files every day. This daily backup approach keeps the AI file relatively small and ensures that the AI file is archived on a regular schedule. You can also use the After Image File Management Utility to archive and empty your AI files. For more information, see AIFile Management utility.