Use systemd-run in server-backup.

if [ "$#" -eq 0 ]

then

    ssh -t host01.shore.co.il -o \

        "RemoteCommand tmux new-session -As backup sudo sh -c 'mount /dev/sdb1 /mnt && offsite-backup /mnt && umount /mnt'"

        "RemoteCommand sudo mount /dev/sdb1 /mnt"

    ssh host01.shore.co.il -o \

        "RemoteCommand sudo -H systemd-run --unit server-backup --collect  sh -c 'offsite-backup /mnt && umount /mnt'"

elif [ "$1" = '-c' ]

then

    if ssh host01.shore.co.il tmux has-session -t backup 2>/dev/null

    if ssh host01.shore.co.il systemctl --system is-failed server-backup.service >/dev/null

    then

        echo 'Backup failed.'

        exit 1

    elif ssh host01.shore.co.il systemctl --system is-active server-backup.service >/dev/null

    then

        echo 'Backup is still running.'

    else