El Capitan, can't rsync, tar, cp certain files on Promise raid
I'm not an expert by any means, but when I use rsync I use the flags -vaE --progress. I believe one of those flags (I don't remember which) allows you to copy files which may be corrupt and which the GUI (Finder) copy will get hung up on. So the syntax I use is:

$ sudo rsync -vaE --progress [source path] [destination path]


I'd try using one or more of those flags in the command. Let me know if this helps you at all.