Script to perform restic backup on an LVM volume without it filling up

restic.sh

# <add spaces to keep out of bash hist>    export RESTIC_PASSWORD=""
# run this command with sudo -E ./restic.sh

########

lvcreate -L 20G -s -n backup-snapshot /dev/new_root/lv0 || exit 1
mount /dev/new_root/backup-snapshot /home/arthurdent/NAS/backup-snapshot || exit 1

export B2_ACCOUNT_ID="XXXXXXXXXX"
export B2_ACCOUNT_KEY="XXXXXXXXXXX"

#source ~/scripts/restic.sh

# restic_bin = "~/Programs/restic_0.12.1_linux_amd64/restic"


#sudo -E restic -r b2:DeepThought-Ryzen-restic backup /home/arthurdent/NAS/backup-snapshot
restic_cmd="/home/arthurdent/Programs/restic_0.12.1_linux_amd64/restic -r b2:DeepThought-Ryzen-restic backup  /home/arthurdent/NAS/backup-snapshot --cache-dir /home/arthurdent/NAS/primary_a/.restic_cache/ &"

eval "$restic_cmd"
restic_pid=$!


while true
do
    
    snap_percent="$(lvs -o snap_percent --no-headings)"
    # echo $snap_percent
    snap_percent="$( printf "%.0f" $snap_percent )"

    sleep 5

    # if ! kill -0 "$restic_pid"; then
    #     echo "complete"
    #     exit 1
    # fi

    lvm_full=$(( $snap_percent >= 50 ))

    if ! [ $lvm_full -eq 0 ]; then
        echo "LVM full, reloading"

        killall -INT restic

        umount /home/arthurdent/NAS/backup-snapshot
        yes | lvremove /dev/new_root/backup-snapshot

        lvcreate -L 20G -s -n backup-snapshot /dev/new_root/lv0 || exit 1
        mount /dev/new_root/backup-snapshot /home/arthurdent/NAS/backup-snapshot || exit 1

        eval $restic_cmd
        restic_pid=$!
    fi  
done

 

umount /home/arthurdent/NAS/backup-snapshot
yes | lvremove /dev/new_root/backup-snapshot