Automatic Hard Disk Scrubbing and repair in an X5 Database Machine involves several mechanisms to ensure data integrity and performance. Disk repair can be done immediately using Smart Flash Cache when the corresponding data on the disk is clean, reducing the time needed for corrections. Hard disks are scanned every two weeks by default, but this operation is carefully managed to run only when disks are idle to avoid impacting performance. Additionally, repairs can also utilize another mirror copy if the corrupt area is part of a Normal or High Redundancy Disk Group, ensuring data availability and redundancy.