S3 has no rename or move operation.
Renaming is CopyObject and then DeleteObject.
CopyObject takes linear time to the size of the file(s).
This comes up fairly often when someone has written a lot of files
to the wrong place - moving the files back is very slow.
This is right:
In a normal file system, renaming a directory is fast O(1), in S3 it's slow O(all recursive children).
And Amazon S3 has not added a delimiter-based function to reduce its complexity, even though that would be easily possible in a lexicographic prefix tree (re-rooting the subtree).
So here the original post has indeed found a case where S3 is much slower than a normal file system.
In a normal file system, renaming a directory is fast O(1), in S3 it's slow O(all recursive children).
And Amazon S3 has not added a delimiter-based function to reduce its complexity, even though that would be easily possible in a lexicographic prefix tree (re-rooting the subtree).
So here the original post has indeed found a case where S3 is much slower than a normal file system.