Событие DegradedArray на / dev / md2

Я получаю следующую ошибку на моем сервере Proxmox. Это происходило несколько раз за последние несколько дней. Как я могу проверить, неисправен ли жесткий диск RAID?

    This is an automatically generated mail message from mdadm
running on myserver

A DegradedArray event had been detected on md device /dev/md2.

Faithfully yours, etc.

P.S. The /proc/mdstat file currently contains the following:

Personalities : [raid1] 
md4 : active raid1 sda4[0] sdb4[1]
      1931980736 blocks [2/2] [UU]
      bitmap: 2/15 pages [8KB], 65536KB chunk

md2 : active raid1 sda2[0]
      20478912 blocks [2/1] [U_]

unused devices: <none>

parted -l

Model: ATA HGST HUS724020AL (scsi)
Disk /dev/sda: 2000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system     Name     Flags
 1      20.5kB  1049kB  1029kB                  primary  bios_grub
 2      2097kB  21.0GB  21.0GB  ext3            primary  raid
 3      21.0GB  22.0GB  1073MB  linux-swap(v1)  primary  raid
 4      22.0GB  2000GB  1978GB                  logical  raid


Model: ATA HGST HUS724020AL (scsi)
Disk /dev/sdb: 2000GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start   End     Size    File system     Name     Flags
 1      20.5kB  1049kB  1029kB                  primary  bios_grub
 2      2097kB  21.0GB  21.0GB                  primary  raid
 3      21.0GB  22.0GB  1073MB  linux-swap(v1)  primary
 4      22.0GB  2000GB  1978GB                  logical  raid


Model: Linux device-mapper (linear) (dm)
Disk /dev/mapper/pve-data: 1974GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number  Start  End     Size    File system  Flags
 1      0.00B  1974GB  1974GB  ext3


Model: Linux Software RAID Array (md)
Disk /dev/md2: 21.0GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number  Start  End     Size    File system  Flags
 1      0.00B  21.0GB  21.0GB  ext3


Error: /dev/md4: unrecognised disk label
Model: Linux Software RAID Array (md)
Disk /dev/md4: 1978GB
Sector size (logical/physical): 512B/512B
Partition Table: unknown
Disk Flags: