Which backup type requires the least amount of storage space over time?

Incremental backups are designed to save storage space effectively over time. This type of backup only captures the changes made since the last backup was performed, whether that last backup was a full backup or another incremental backup.

Because only the new or modified data is stored each time, incremental backups require significantly less storage compared to full backups, which save all files regardless of whether they have changed since the last backup.

While mirror backups create an exact replica of the data at the time of the backup, they also occupy more storage due to capturing all current files. Hybrid backups may incorporate elements of both incremental and full backups but can still lead to higher storage usage than pure incremental backups, particularly if they include full backup segments.

Therefore, due to their selective capture of only changed data, incremental backups efficiently minimize the overall storage requirements over an extended period.