2.2.1.2 Verifying the Disk Controller Configuration on Systems Without a RAID Controller

Commencing with Oracle Exadata X9M-2, two-socket Exadata database servers have no RAID controller. For eight-socket systems, all models starting with Oracle Exadata X7-8 have no RAID controller.

• View /proc/mdstat to see the database server disk controller configuration.

  The following example shows a typical disk controller configuration file from an Exadata X9M-2 database server:

  [root@dbnode09adm01 ~]# cat /proc/mdstat 
  Personalities : [raid1] 
  md34 : active raid1 nvme3n1[1] nvme1n1[0]
        3125613568 blocks super external:/md126/0 [2/2] [UU]
        
  md24 : active raid1 nvme2n1[1] nvme0n1[0]
        262144000 blocks super external:/md127/0 [2/2] [UU]
        
  md25 : active raid1 nvme2n1[1] nvme0n1[0]
        2863467520 blocks super external:/md127/1 [2/2] [UU]
        
  md126 : inactive nvme3n1[1](S) nvme1n1[0](S)
        6306 blocks super external:imsm
         
  md127 : inactive nvme2n1[1](S) nvme0n1[0](S)
        6306 blocks super external:imsm
         
  unused devices: <none> 

  The following shows a typical disk controller configuration file from an Exadata X10M database server:

  [root@dbnode10adm01 ~]# cat /proc/mdstat 
  Personalities : [raid1]
  md25 : active raid1 nvme0n2[0] nvme1n2[1]
         3738885120 blocks super 1.2 [2/2] [UU]
         bitmap: 3/28 pages [12KB], 65536KB chunk
  
  md24 : active raid1 nvme0n1[0] nvme1n1[1]
         7819456 blocks super 1.2 [2/2] [UU]
         bitmap: 0/1 pages [0KB], 65536KB chunk
  
  unused devices: <none>

If your output is substantially different, then investigate and correct the problem. In particular, degraded virtual drives usually indicate absent or failed physical disks. Disks that show [1/2] and [U_] or [_U] for the state indicate that one of the NVME disks is down. Failed disks should be replaced quickly.