Which backup type only copies data that has changed since the last full backup?

The backup type that only copies data that has changed since the last full backup is known as a differential backup. This method compares the current state of the data to the last full backup and captures any changes made during that period. When restoring data from a differential backup, you need the last full backup and the most recent differential backup, allowing for a straightforward recovery process.

In contrast, an incremental backup captures only the data that has changed since the last backup of any type, be it a full or incremental backup. A full backup, on the other hand, copies all selected data regardless of changes. A snapshot backup provides a point-in-time representation of data but does not focus specifically on capturing changed data. Understanding these differences is crucial for effective data management and recovery strategies in Linux systems and beyond.