Does this happen for full backup? What is the client OS and file system used? Did you try save from client side and what happens then? If it fails, does it fail always at the same file/directory? Are you sure that data backup is done and it is index that fails? If yes, what happens when you do "no index save" backup? Do you have firewall between client and server/storage node? When this happens what TCP connections do you see open? What does the log on client side say? etc....