Controller surface scan

Controller surface scan analysis is an automatic background process that ensures that you can recover data if a drive failure occurs. The controller scanning process

• checks physical drives in fault-tolerant logical drives for bad sectors

• in RAID 5 or RAID 6 (ADG) configurations, verifies the consistency of parity data

You can disable the surface scan analysis, set it to high, or specify a time interval that the controller is inactive before a surface scan analysis is started on the physical drives that are connected to it.

• Disabled: Disabling the controller surface scan can decrease the potential latency impacts that may occur due to waiting for a scanning I/O to complete, but at the cost of not detecting the growth of bad blocks on the media before a data loss situation.

• High: Setting the controller surface scan to high increases the probability of detecting a bad block before it becomes a data loss situation.

• Idle: Setting the controller surface scan to idle and setting the corresponding surface scan delay can decrease the potential latency impacts, but still allow the scanning of bad blocks during the idle time.

Parallel surface scan count allows the control of how many controller surface scans can operate in parallel. This is used when there is more than one logical drive on a controller. This setting allows the controller to detect bad blocks on multiple logical drives in parallel and can significantly decrease the time it takes to detect back, especially for logical drives using very large capacity drives.