mkdir /mnt/usb
  mount -t vfat /dev/sda1 /mnt/usb

then to delete a backup to save some space in the archive:

  cd /var/www
  ls -al

find the backup ending in .tar.gz and remove it:

  rm file.tar.gz (where this is the filename you found as the backup)

in order to backup the folders we need, type this:

  tar -cvzf backup31aug.tar.gz /var /etc /home /usr

This is the backup archive we will save.