Hello The md manual says that "If all blocks read successfully but are found to not be consistent, then this is regarded as a mismatch." whereas blocks that suffer from a read error are not counted as mismatches. It then describes the action "If repair was used, then a mismatch will be repaired in the same way that resync repairs arrays. For RAID1, all but one block are overwritten with the content of that one block." If there has been no read error then how does it know which block is good? Andrew -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html