diff --git a/doc/tips/local_caching_of_annexed_files/comment_19_490c15d7673c535e83c7f1df3082e7ed._comment b/doc/tips/local_caching_of_annexed_files/comment_19_490c15d7673c535e83c7f1df3082e7ed._comment
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+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 19"""
+ date="2018-12-03T17:34:10Z"
+ content="""
+git-annex looks at the file's stat() and only if the device id is the same
+as the stat of the destination directory does it use `cp`. If you see it
+running `rsync` instead, it's under the perhaps mistaken impression that
+it's a cross-device copy.
+"""]]