[[!comment format=mdwn
 username="http://joey.kitenet.net/"
 nickname="joey"
 subject="don't do that"
 date="2012-03-19T18:23:13Z"
 content="""
Suppose you do that to repos A and B. Now, in A, you `git annex drop` a file that is only present in those repositories. A checks B to make sure it still has a copy of the file. It sees the (same) file there, so assumes it's safe to drop. The file is removed from A, also removing it from B, and losing data.

It is possible to configure A and B to mutually distrust one-another and avoid this problem, but there will be other problems too.

Instead, git-annex supports using `cp --reflink=auto`, which on filesystems supporting Copy On Write (eg, btrfs), avoids duplicating contents when A and B are on the same filesystem.
"""]]