Synology NAS DS212J Disk 1 disappeared

20190825 Synology DS212J 2 bay NAS is not seeing Disk 1

Symptoms:

  • NAS alert beeping
  • Logged into admin, dashboard showed Raid 1 (Mirrored) 2 drive array degraded
  • Storage manager -> HDD only showing Disk 2, no Disk 1 showing
  • Moved NAS contents elsewhere
  • Deleted Storage volume 1 to hopefully speed up any rebuild

Solution Attempt 1 (Success = NO):

  • Replaced Disk 1, still the same problem, cannot see Disk 1

Solution Attempt 2 (Success = YES, can see Disk 1 in Storage manager):

  • Disk 1 is connected to the main board by a plugin riser
    • Removed both disks
    • Removed disk brackets screws, removed frame/riser
    • and applied contact cleaner to both ends
    • Fitted riser inserting/removing a couple of times
  • Refitted both disks
  • On power up, logged into admin panel, can see both disks
    • Disk 1 showing system partition failed
  • Initiated repair on the volume etc