Raid5分区无法返回

有时接触不良会导致一个磁盘与 raid5 阵列断开连接。现在我拿不回光盘了。错误弹出。什么是无效论点？

# mdadm /dev/md/2 --add /dev/sda5 
mdadm: add new device failed for /dev/sda5 as 3: Invalid argument

# mdadm --brief /dev/md2                     
/dev/md2: 857.19GiB raid5 3 devices, 0 spares. Use mdadm --detail for more detail.

# cat /proc/mdstat                  
Personalities : [raid6] [raid5] [raid4] 
md2 : active raid5 sdb5[4] sdc2[2]
      898834048 blocks super 1.0 level 5, 64k chunk, algorithm 2 [3/2] [_UU]
      
md0 : active raid5 sdb3[1] sda6[4] sdc1[3]
      976768512 blocks super 1.0 level 5, 128k chunk, algorithm 2 [3/3] [UUU]
      bitmap: 2/4 pages [8KB], 65536KB chunk

unused devices: <none>

# mdadm --detail /dev/md2       
/dev/md2:
           Version : 1.0
     Creation Time : Tue May 31 14:33:33 2016
        Raid Level : raid5
        Array Size : 898834048 (857.19 GiB 920.41 GB)
     Used Dev Size : 449417024 (428.60 GiB 460.20 GB)
      Raid Devices : 3
     Total Devices : 2
       Persistence : Superblock is persistent

       Update Time : Sat Oct 31 17:50:30 2020
             State : clean, degraded 
    Active Devices : 2
   Working Devices : 2
    Failed Devices : 0
     Spare Devices : 0

            Layout : left-symmetric
        Chunk Size : 64K

Consistency Policy : resync

              Name : any:2
              UUID : c4c80dbb:9b5cd068:fe33283e:63397104
            Events : 2813

    Number   Major   Minor   RaidDevice State
       -       0        0        0      removed
       4       8       21        1      active sync   /dev/sdb5
       2       8       34        2      active sync   /dev/sdc2

第二次尝试：

# dd if=/dev/zero of=/dev/sda5 bs=1M count=200
200+0 records in
200+0 records out
209715200 bytes (210 MB, 200 MiB) copied, 2.12945 s, 98.5 MB/s

# mdadm /dev/md2 --add /dev/sda5 
mdadm: add new device failed for /dev/sda5 as 3: Invalid argument

# dmesg
[ 8463.999268] md: sda5 does not have a valid v1.0 superblock, not importing!
[ 8463.999274] md: md_import_device returned -22