This section assumes that you are familiar with basic concepts related to backups.
Backups can be categorized in several ways:
Full backup and incremental backup A full backup is a backup of both the database file and of the transaction log. See Making a full backup.
An incremental backup is a backup of the transaction log only. Typically, full backups are interspersed with several incremental backups. See Making an incremental backup.
Server-side backup and client-side backup To execute a server side backup, you execute the BACKUP statement or use the dbbackup -s option; the database server then performs the backup. You can easily build server side backup into applications because it is a SQL statement. Also, server-side backup is generally faster because the data does not have to be transported across the client/server communications system. See BACKUP statement.
You can execute an online backup from a client computer using the Backup utility.
Archive backup and image backup An archive backup copies the database file and the transaction log into a single archive file, typically on a tape drive. An image backup makes a copy of the database files and/or the transaction log, each as separate files. You can only perform archive backups as server-side backups, and you can only make full backups.
You should use an archive backup if you are backing up directly to tape. Otherwise, an image backup has more flexibility for transaction log file management. See Backing up a database directly to tape.
Online backup and offline backup Backing up a running database provides a snapshot of a consistent database, even though other users are modifying the database. An offline backup consists simply of copying the files. You should only perform an offline backup when the database is not running, and when the database server was shut down properly.
The information in this chapter focuses on online backups.
Live backup A live backup is a continuous backup of the database that helps protect against total computer failure.
You can use a live backup to provide a redundant copy of the transaction log. This copy can be used to restart a secondary system in case the primary system running the database server becomes unusable. A live backup runs continuously, terminating only if the server shuts down. If you suffer a system failure, the backed up transaction log can be used for a rapid restart of the system. However, depending on the load that the server is processing, the live backup may lag behind and may not contain all committed transactions.