http://svn.haxx.se/dev/archive-2011-02/0582.shtml
It should be possible to implement "svnadmin hotcopy --incremental" for FSFS
repositories. This would only need to copy rev files newer than HEAD of the old
copy, rather than all the rev files.
An incremental hotcopy would need to account for changes in packing, both of rev
files and revprop files.
It would need some strategy to deal with old revprops: copy all of them, read
and copy those that have changed, copy those with newer timestamps.
Finally it would need to deal with exclusive file locks, probably by deleting
all the locks and copying a new set. See also issue #3750.
http://svn.haxx.se/dev/archive-2011-02/0582.shtml
New Feature
Major