TLDR: They got an error from the RAID1 array, but they re-added the broken drive to the array. Also, they did’t have backups. Then, they did fsck -y on the fi

TLDR: They got an error from the RAID1 array, but they re-added the broken drive to the array. Also, they did’t have backups. Then, they did fsck -y on the filesystems on the array incorporating the broken drive. What they probably should have done first is remove the broken drive from the array again.