To backup your home directory to an external hard drive, you can use the following tar command.

sudo tar -cvpzf - /home/user/ | split -b 1000m - /media/Daten/homebackup.tgz.split.

This should create a tar of your home folder, zipped and splitted into 1GB pieces and saved to the external hdd named Daten.

To join the files just do something like this: cat homebackup.tgz.split* > homebackup.tgz after that you can extract it again with tar.