BBM keeps a log of bad blocks for each drive to allow the system track each bad block directly without effect whole disk. BBM is particularly useful for RAID, as it allows them to retain redundancy of bad blocks on all stripes. With this feature, a RAID can still remain functional even when the RAID is rebuilding.
* Please note that BBM only supports RAID 5 or RAID 6 that were created with firmware 4.2.0 (or newer). RAID created with an older firmware will not support BBM even if the firmware is updated.