Your backup will be stored differently differently depending on the backup format selected (this option replaces the Backup Engine selection in versions 1.43.2 and earlier).
An
Archive backup packs all of the files into a single (often large) "tar" archive file. Unfortunately, Archive backups do not support incremental backups; a full snapshot must be created each time. Archive backups support both gzip and bzip2 on-the-fly compression. This backup format was formerly called the "tar" backup engine (".gz" or ".bz2" was appended if gzip or bzip2 compression was enabled, respectively).
Reducing backup size with compression
Enabling compression will utilize more system resources during the backup, but results in smaller file sizes. gzip is a relatively lightweight compression with a good compression ratio. If you would like to further reduce the size of your backups, consider switching to bzip2 compression. Although it is much slower than gzip, bzip2 is able to achieve smaller file sizes.
A
Direct copy backup will simply copy your files and their folder structure as-is, similar to a drag-and-drop copy in your file browser. Although this backup type does not support compression, incremental backups are available. This backup format was formerly called the "rsync" backup engine.
Increasing backup speed
Enabling the Backups are incremental option will run an incremental backup instead of a full one, copying only the changes since your last backup. Currently, the incremental backups are only available for set backups on Unix-like platforms (such as Linux and OS X) and cannot be used when backing up to a remote host.
Additionally, running an incremental backup will update the backup folder in-place so no old backups will be kept if you choose to enable incremental backups.