[[!comment format=mdwn
 username="joey"
 subject="""comment 1"""
 date="2015-09-18T16:47:02Z"
 content="""
A rename operation could be added to the interface for remotes. I suspect
most remotes wouldn't be able to implement it (could hubic?), but it could
be used when available.

I'm not sure what to do in the migrate command to make it use such an
interface though. It could try to move the files to their new names on each
remote that supports the interface. But what about remotes that cannot be
accessed?

Could make a `git annex migrate --on remote`, to 
migrate remotes peicemeal. Which would have to look back in the git history
to find the old key that a file had been migrated from.
Although then the user has to be careful to specify the same set of
files that were migrated before.
"""]]
