What is raid scrubbing?

Raid scrubbing is a process that identifies and corrects errors in the data stored on a redundant array of independent disks (RAID). It's also known as RAID patrol scrubbing or RAID consistency checking.

During normal operation of the RAID, data is constantly written, read, and rewritten. Over time, bit errors can occur, which can lead to data inconsistencies and corrupted data. RAID scrubbing is essential for detecting and correcting these errors before they cause irreparable damage.

The scrubbing process involves reading all the data from the RAID disks and checking it against a known good checksum. If an error is detected, the RAID controller will attempt to correct it using redundancy data stored on the disks. If the error cannot be corrected, the controller will mark the affected area as bad and prevent further use of that sector.

Raid scrubbing can be performed manually or automatically on a scheduled basis. It's recommended to schedule regular RAID scrubbing to maintain data integrity and prevent data loss. However, it's important to note that scrubbing can be a resource-intensive process that can affect the performance of the RAID system.