{{tag>[Hardware storage synology]}}
=====Synology - verify RAID=====
These steps below verifies the consistency of RAID, but not if the contents of data is correct!
  * Find the RAID (md) device you want to check:<code>cat /proc/mdstat 
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] 
md2 : active raid6 sda3[0] sdgd3[7] sdgc3[6] sdgb3[5] sdga3[4] sdd3[8] sdc3[2] sdb3[1]
      11692753536 blocks super 1.2 level 6, 64k chunk, algorithm 2 [8/8] [UUUUUUUU]
      
md1 : active raid1 sda2[0] sdb2[1] sdc2[2] sdd2[3]
      2097088 blocks [4/4] [UUUU]
      
md0 : active raid1 sda1[0] sdb1[1] sdc1[2] sdd1[3]
      2490176 blocks [4/4] [UUUU]
      
unused devices: <none></code>
  * Start scrub process:<code>echo check > /sys/block/md2/md/sync_action</code>
  * This will scrub your array and count any bit mismatches in: <code>cat /sys/block/md2/md/mismatch_cnt</code>
  * Then you can repair the mismatching blocks with: <code>echo repair > /sys/block/md2/md/sync_action</code>
  * Monitor progress: <code>cat /proc/mdstat
Personalities : [linear] [raid0] [raid1] [raid10] [raid6] [raid5] [raid4] 
md2 : active raid6 sda3[0] sdgd3[7] sdgc3[6] sdgb3[5] sdga3[4] sdd3[8] sdc3[2] sdb3[1]
      11692753536 blocks super 1.2 level 6, 64k chunk, algorithm 2 [8/8] [UUUUUUUU]
      [>....................]  check =  0.0% (109008/1948792256) finish=893.6min speed=36336K/sec
      
md1 : active raid1 sda2[0] sdb2[1] sdc2[2] sdd2[3]
      2097088 blocks [4/4] [UUUU]
      
md0 : active raid1 sda1[0] sdb1[1] sdc1[2] sdd1[3]
      2490176 blocks [4/4] [UUUU]
      
unused devices: <none></code>