Decision tree for backup types

There are different backup types and each has its advantages and disadvantages. Different backup types can be combined. For example, every months a full backup can be created with tar and in between a weekly rsync delta backup. However, this requires manual configuration of Systemd timers and requires good Systemd knowledge. The raspiBackupInstaller configures only one backup type.

All backup types can be completely restored with raspiBackup. A dd backup can also be restored wth a Windows system.

A dd backup creates a consistent binary image of the system. The entire device with the system is always read and backed up. This means that data that has not changed is also backed up. It also means that the restore device must be at least as large as the original system for the restore. No partition is resized. This causes problems especially with SD cards, as the SD cards - although 32GB in size, for example - always have slight differences and therefore a restore of a 32GB system to another 32GB SD card may fail because the SD card is slightly smaller.

But it is not recommended to use the backup type dd. Explanations are given in Why should you not use dd as a backup type? in detail.

A ddz backup, like a dd backup, backs up the entire system. This method puts a heavy load on the CPU as the amount of data is reduced. (It is a dd backup with zipping switched on with -z). A restore with Windows tools is not possible.

A tar backup backs up all the data stored on the system device, although the backup is not not as large as an dd backup, as only the data that actually exists is backed up. Therefore, a tar backup can also be restored on devices that is smaller than the original device. Of course, only if all data fits on the new device.

A tgz backup backs up the entire system, like a tar backup. This method puts a heavy load on the CPU as the amount of data is reduced. (It is a tar backup with zipping switched on with -z)

An rsync backup only saves the data that has changed since the last backup, except for the first time. The hard links of the ext3/ext4 file system file system ensures that the backup is still consistent. However, the data is not compressed. However, this in turn has the advantage that you can easily retrieve individual files from the backup by just copying them. This method is very fast if an initial initial backup has already been created.