There are three main means of 'backup' on Unix - ANY flavour: tar, cpio, and dd
DD is the most robust program of ANY operating system in cloning a disk drive. Tar is the easiest (Tape ARchive) and works disk to disk, disk to floppy, disk to tape, etc. There are various wrappers to make tar easier to extract/retrieve individual files from an archive. DD is the fastest, cpio the slowest and more of bitch to use than the other two.
Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good ...