I've been using cpio to do file backups for a while now but only recently had to restore from them. Here's the command I use for duplicating a filesystem to another filesystem:
find . -print -xdev | cpio -pdm /media/sdb3
Here is is with gzip to a file
find . -print -xdev | cpio -ocv | gzip -c > filename.cpio.gz
Here is the extract
cpio -idmv --no-absolute-filenames < filename.cpio
Here is extract with gzip
gunzip -c < filename.cpio.gz | cpio -idmv --no-absolute-filenames
And here is how to ssh to a remote machine and copy a filesystem from the remote to the current directory on the local
ssh root@minimyth2 "find / -depth -print -xdev | cpio -oaV" | cpio -imVd --no-absolute-filenames