Data consistency checking Functions

What is data consistency checking?
Data consistency checking refers to the checking of consistency of the data and parity that are distributed to multiple HDD units in a redundant RAID structure. In RAID1, both HDD units in a mirroring structure are compared (when data mismatch is detected, data consistency can be restored by overwriting the data of the predetermined HDD in the other HDD). In RAID5, the parity is calculated from the data and the parity is compared with the parity that has been stored (if the parities do not match, data consistency can be restored by regenerating the parities). The following effects can be expected by checking the consistency periodically.

(1) Preventing an error occurring at data restoration
Correct read errors of all the areas by periodically checking the consistency. Data cannot be restored when errors occur in multiple HDD units. Therefore, it is important to prevent read errors from occurring in the area when a degenerated state occurs.

Example: An error occurred in one HDD in the configuration of RAID5 HDD x 3 units