Which backup method restores data from a previous backup only for changed files since the last backup?

The incremental backup method is designed to save only the data that has changed since the last backup, whether that last backup was a full backup or another incremental one. This approach ensures that only new or modified files are stored, which can significantly reduce both the storage space required and the time needed to perform the backup.

When using incremental backups, the restoration process involves retrieving the last full backup along with each incremental backup made since that point. This means the restoration could require multiple backup sets, but it is efficient in terms of backup time and storage usage.

In contrast, a full backup captures all files each time a backup is conducted, ensuring that there is a complete snapshot of the data, but it requires significantly more time and storage space. A mirror backup creates an exact copy of the data at the time of the backup, but it does not maintain historical versions of files that were modified or deleted after subsequent backups. Differential backups save changes made since the last full backup but require more storage than incremental backups, as each new differential backup includes all changes from the last full backup, not just those from the last backup.