20260221072521 mdadmを確認したら1つ使われていなかった

20240409145451 USB HDDをRAID5にする で作ったRAID5を見にいったら、

mdadm --detail /dev/md1
/dev/md1:
           Version : 1.2
     Creation Time : Wed Feb 19 11:53:11 2025
        Raid Level : raid5
        Array Size : 11720777728 (10.92 TiB 12.00 TB)
     Used Dev Size : 5860388864 (5.46 TiB 6.00 TB)
      Raid Devices : 3
     Total Devices : 2
       Persistence : Superblock is persistent

     Intent Bitmap : Internal

       Update Time : Sat Feb 21 07:09:12 2026
             State : clean, degraded 
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

            Layout : left-symmetric
        Chunk Size : 512K

Consistency Policy : bitmap

              Name : kinorr:1  (local to host kinorr)
              UUID : 12a4a854:7e3bebc3:34df16ae:91b47e7b
            Events : 47469

    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       -       0        0        1      removed
       3       8       33        2      active sync   /dev/sdc1

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 2
   Array State : A.A ('A' == active, '.' == missing, 'R' == replacing)

などと表示され、1つdiskが使われていない。sdb1が使われていない。

# mdadm --examine /dev/sdb1
/dev/sdb1:
          Magic : a92b4efc
        Version : 1.2
    Feature Map : 0x9
     Array UUID : 12a4a854:7e3bebc3:34df16ae:91b47e7b
           Name : kinorr:1  (local to host kinorr)
  Creation Time : Wed Feb 19 11:53:11 2025
     Raid Level : raid5
   Raid Devices : 3

 Avail Dev Size : 11720777728 sectors (5.46 TiB 6.00 TB)
     Array Size : 11720777728 KiB (10.92 TiB 12.00 TB)
    Data Offset : 264192 sectors
   Super Offset : 8 sectors
   Unused Space : before=264112 sectors, after=0 sectors
          State : active
    Device UUID : c2697da3:050903a8:91332e32:73059cef

Internal Bitmap : 8 sectors from superblock
    Update Time : Sat Feb  7 03:14:25 2026
  Bad Block Log : 512 entries available at offset 32 sectors - bad blocks present.
       Checksum : 3fce2bb0 - correct
         Events : 40399

         Layout : left-symmetric
     Chunk Size : 512K

   Device Role : Active device 1
   Array State : AAA ('A' == active, '.' == missing, 'R' == replacing)

設定はされているっぽい。

mdadm --manage /dev/md1 --add /dev/sdb1

で再度追加で大丈夫になった。