サーバーのHDD認識エラー

ZIKUUのアプリケーションサーバーのバックアップ用外付けHDDが認識されなくなりました。

このHDDは、夜間にRAIDディスク（データベースやファイルサーバーのデータが入っている）からインクリメンタルバックアップをするために使われています。

RAIDディスク側に問題がなければ慌てる必要はありませんが、もしものことはいつ起きるかわかりません。

急いでバイクを飛ばして塾に来て復旧作業をやりました。

復旧作業と言っても、外付けHDDのケーブルの抜き差し、電源の再投入などの簡単な作業をして、HDDをマウントできるかを確認しただけ。

以下、マウントの確認に使ったコマンドです。

➜  ~ lsblk -o NAME,MODEL,SERIAL,SIZE,TYPE,FSTYPE,LABEL,UUID,MOUNTPOINTS

NAME    MODEL         SERIAL         SIZE TYPE  FSTYPE       LABEL           UUID                                 MOUNTPOINTS
loop0                               63.8M loop  squashfs                                                          /snap/core20/2769
loop1                               63.8M loop  squashfs                                                          /snap/core20/2866
loop2                                 74M loop  squashfs                                                          /snap/core22/2411
loop3                               91.7M loop  squashfs                                                          /snap/lxd/38800
loop4                              115.1M loop  squashfs                                                          /snap/lxd/40115
loop5                               50.1M loop  squashfs                                                          /snap/snapd/27406
loop6                               50.1M loop  squashfs                                                          /snap/snapd/27591
sda     WDC WD60EZAX- WD-WX72AC26F   5.5T disk                                                                    
└─sda1                               5.5T part  linux_raid_m zikuu-serv-01:0 0273aeac-525f-31a2-2602-555315c57884 
  └─md0                              5.5T raid1 ext4                         a5a71989-e858-4f72-88a9-8f7a22fe2531 /export/workspaces
                                                                                                                  /mnt/share
sdb     WDC WD60EZAX- WD-WXU2A238X   5.5T disk                                                                    
└─sdb1                               5.5T part  linux_raid_m zikuu-serv-01:0 0273aeac-525f-31a2-2602-555315c57884 
  └─md0                              5.5T raid1 ext4                         a5a71989-e858-4f72-88a9-8f7a22fe2531 /export/workspaces
                                                                                                                  /mnt/share
sdc     LHR USB Devic DS05EU300000   3.6T disk                                                                    
└─sdc1                               3.6T part  ext4         WD_Red_4T       e2c5061a-0e3d-4d04-9483-710801a9f9f1 /mnt/backup
nvme0n1 WD_BLACK SN77 23170K802496 931.5G disk                                                                    
├─nvme0n1p1
│                                      1G part  vfat                         51B0-21A4                            /boot/efi
└─nvme0n1p2
                                   930.5G part  ext4                         d077971a-797f-410e-8370-481bc9c359e4 /
➜  ~ ls -l /dev/disk/by-label/

total 0
lrwxrwxrwx 1 root root 10 Jul 29 16:13 WD_Red_4T -> ../../sdc1
➜  ~ df -h /mnt/backup

Filesystem      Size  Used Avail Use% Mounted on
/dev/sdc1       3.6T  353G  3.1T  11% /mnt/backup
➜  ~ systemctl status mnt-backup.mount mnt-backup.automount --no-pager
● mnt-backup.mount - /mnt/backup
     Loaded: loaded (/etc/fstab; generated)
     Active: active (mounted) since Wed 2026-07-29 16:12:50 JST; 4min 32s ago
TriggeredBy: ● mnt-backup.automount
      Where: /mnt/backup
       What: /dev/sdc1
       Docs: man:fstab(5)
             man:systemd-fstab-generator(8)

● mnt-backup.automount
     Loaded: loaded (/etc/fstab; generated)
     Active: active (running) since Wed 2026-07-29 16:03:23 JST; 13min ago
   Triggers: ● mnt-backup.mount
      Where: /mnt/backup
       Docs: man:fstab(5)
             man:systemd-fstab-generator(8)

Jul 29 16:03:23 zikuu-serv-01 systemd[1]: mnt-backup.automount: Directory /mnt/backup to mount over is not empty, mounting anyway.
Jul 29 16:03:23 zikuu-serv-01 systemd[1]: Set up automount mnt-backup.automount.
Jul 29 16:06:07 zikuu-serv-01 systemd[1]: mnt-backup.automount: Got automount request for /mnt/backup, triggered by 17585 …are/webm)
Jul 29 16:06:18 zikuu-serv-01 systemd[1]: mnt-backup.automount: Got automount request for /mnt/backup, triggered by 17747 …are/webm)
Jul 29 16:07:52 zikuu-serv-01 systemd[1]: mnt-backup.automount: Got automount request for /mnt/backup, triggered by 20782 …are/webm)
Jul 29 16:10:49 zikuu-serv-01 systemd[1]: mnt-backup.automount: Got automount request for /mnt/backup, triggered by 27203 (df)
Jul 29 16:10:59 zikuu-serv-01 systemd[1]: mnt-backup.automount: Got automount request for /mnt/backup, triggered by 27203 (df)
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