Which type of backup involves copying only new or modified files since the last backup?

The type of backup that involves copying only new or modified files since the last backup is known as an incremental backup. This method is efficient because it saves time and storage space by only targeting the files that have changed since the last backup operation, whether that was a full or another incremental backup.

In an incremental backup, after the initial full backup, each subsequent backup captures only the data that has been altered or newly created since the last backup. This means faster backup times and reduced resource usage, as fewer files are being processed compared to a full backup, which captures everything.

The other types of backups serve different purposes: a full backup captures all files regardless of changes, a differential backup saves changes made since the last full backup, and a mirror backup creates an exact copy of data but does not keep older versions. Each serves distinct roles in backup strategies, making the incremental backup particularly useful for minimizing backup time and storage needs while ensuring that all recent changes are protected.