No space left on device

[lienzzzz]

rsync: write failed on "/mnt/var/lib/apt/lists/mirrors.tuna.tsinghua.edu.cn_debian_dists_buster_main_binary-armhf_Packages": No space left on device (28)
rsync error: error in file IO (code 11) at receiver.c(374) [receiver=3.1.3]

$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 29G 1.9G 26G 7% /
devtmpfs 1.7G 0 1.7G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 48M 1.9G 3% /run
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/mmcblk0p1 253M 30M 223M 12% /boot
tmpfs 380M 0 380M 0% /run/user/1000
/dev/sda4 29G 7.6G 22G 27% /media/lienusb
/dev/mapper/loop0p2 2.2G 2.2G 0 100% /mnt

[lienzzzz]

修改
ds=echo $dr $db |awk '{print int(($1+$2)*1.2)}'
为
ds=echo $dr $db |awk '{print int(($1+$2)*1.4)}'
备份成功了