df

disk free

df -lhT              # 查看分区的文件系统类型、大小、挂载点
sudo lsblk -o name,mountpoint,label,size,uuid

df -i -h             # 查看 inode 使用状况

# 查找那个目录文件最多


/var
proc

#FILES=/usr/*
#FILES=/var/*
FILES="
/boot
/dev
/etc
/home
/lost+found
/media
/mnt
/opt
/proc
/root
/run
/srv
/sys
/tmp
/usr
"


for f in $FILES ; do
    echo $f `find $f -xdev -type f|wc -l`
done | sort -g -k2 | column -t


# 通过类似命令，一点点排除，最终发现 /var/lib/docker/devicemapper/mnt 目录下面有 602897 个文件

/dev         0
/lost+found  0
/media       0
/mnt         0
/opt         0
/srv         0
/tmp         3
/home        6
/root        23
/run         299
/boot        326
/etc         1851
/sys         11440
/usr         81147
/proc        148542

ls /var/lib/docker/devicemapper | wc -l

find /var/lib/docker/devicemapper -xdev -type f|wc -l

/var/lib/docker

find /var/lib/docker/devicemapper -xdev -type f|wc -l