Down voted because you disagree? Or you don't know what cpio is? Either way please discuss instead of or in addition to voting.

Your post has no information as to why you'd use cpio.

OK, fair point. cpio doesn't have global data structures that grow with the size of the operation, which cp does have. rsync prior to 3.0 also had to scan the entire job before it would begin the transfer, which can take forever. cpio operates on a stream, in the form of find | cpio , so cpio only sees one file from the stream at a time. Find, at least GNU find, is also written such that its resources don't vary with the amount of output.

rsync is a bit of a kitchen sink, and cp is too simple. cpio is just the thing, and was designed for this exact use case.

Does your setup preserve hard links? Because this is from where OP's problems originated.