If only 5% of your database changes during the day, why back up 100% of the database every night? As databases grow and batch windows continue to shrink, this questions becomes ever more important.

What is Delta Backup ?
Delta Backup is an enhancement to ORBiT's BACKUP/3000 utility. It backs up the changed parts of a file rather than the entire file. This dramatically reduces the amount of time, resources, and tape required for backups.

How does Delta Backup work ?
Delta tracks the changes made to files between backups, then only backs up the parts of the files that changed. The monitoring of the changes is a continuous process, assuring that every disk write is captured.

• The first step is to create a BASELINE backup which has the complete file. During a recovery, you would restore the BASELINE file first. You will want to make a BASELINE backup periodically (say every week or every month, as your schedule allows)
• A monitoring process then tracks the changes made to files for which you have a BASELINE backup
• Next you create DELTA backups for the file. BACKUP/3000 checks the list of changed file blocks (which the monitor processes tracked), and backs up just those parts of the file
• To restore, simply restore the BASELINE and the last Delta backup

How fast is Delta Backup ?
This depends on how much of your data changes from backup to backup. Most data in modern databases is static. On average only 2-5% of a database file will change on a given day. If 5% of your data changes, and you use Delta Backup, then your backup will take 1/20th the time. A backup that once required an entire set of tapes can now fit on a single volume.

Can Delta Backup be performed online ?
Of course. All normal BACKUP/3000 features work with BASELINE and DELTA backup modes.

Why should Delta be important to you ?
The amount of data on your system is growing. With less expensive third party drives now available for MPE/iX systems, you will be under pressure to keep more and more data online. It is important to make sure your backup operations are as efficient as possible. This means backing up as little data as possible, and backing it up as fast as possible. Delta allows you to back up only what has changed - the data that is actively being modified by your users. The savings in time and media are tremendous.