Determining your data backup and recovery strategy

Scheduling routine backups

Make a full backup of each database just after you create it, to provide a base point, and perform full and incremental backups on a fixed schedule thereafter. It is especially important to back up your database after any large number of changes.

Your backup plan depends on:

The load on your system

The size of your database

The number of changes made to the data

The relative importance of faster backups and faster recovery

Determining the type of backup

When you decide whether to do a full, incremental, or incremental_since_full backup, you need to balance the time it takes to create the backup with the time it would take to restore. You also should consider media requirements. A given incremental backup is relatively quick and takes a relatively small amount of space on tape or disk. Full backups are relatively slow and require a lot of space.

Incremental_since_full is somewhere in between. It starts out as equivalent to incremental, but as the database changes and the number of backups since a full backup increases, incremental_since_full can become as time-consuming and media-consuming as a full backup, or worse.

In general, the opposite is true for restore operations. For example, if you need to restore from a very old full backup and a dozen or more incrementals, the restore may take longer and the backup may use up more space than a new full backup.

The obvious advantage of incremental backups is that it is much faster and takes less space to back up only the data that has changed since the last backup, or even since the last full backup, than to back up your entire database. The disadvantage of relying too heavily on incremental backups is that any eventual restore takes longer.

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Sybase 12.4.2 manual Scheduling routine backups, Determining the type of backup, 414