To backup any partition of any file system type with Linux, you can simply run the following command:

dd if=<input_partition> of=<output_file> bs=<byte_count>

# where
<input_partition>:= is the partition you want to backup (this can also be a file if you want to do the reverse). So, e.g. /dev/sda1 for the first partition on the first drive (hence a=drive 1, 1=partition 1, b=drive 2, ...).
<output_file> := is the file you want to write the partition to (this can also be the output partition on restore).
<byte_count> := is the size of your file system's clusters, normally 4096.

dd if=/dev/sda2 of=/d/sda2_partition bs=4096 #for my own reference
tar cvfz sda2_partition.tar.gz sda2_partition # own reference

You can then compress the file using a normal archiver and save a lot of space that way, because dd constructs a file as big as the partition because it reads bit by bit or 4096 bytes multiple times.