why does this rsync commands copy again the same files?

[M. Fioretti]

On Thu, Nov 22, 2012 22:10:04 PM +0100, Reindl Harald wrote:

> >>> rsync -rvt --delete --no-o --no-g /home/z/photo/ /media/Verbatim/photo
> >>
> >> this command has a error
> >> the last aparm is missing a trailing slash
> > 
> > Why would that be an error?
> 
> because i had enough cases with rsync over different partitions
> where the missing trailing slash resulted in copy the whole data to
> the source partition and fill it up

omitting the trailing slash is the way explained by many tutorials and
by the rsync documentation itself if what one wants to do is, as in my
case, to copy the whole content of /home/z/photo/ inside
/media/Verbatim/photo

IIRC, adding a trailing slash /media/Verbatim/photo/ would cause
another "photo" folder to appear inside /media/Verbatim/photo/, which
is not what I want.

FWIW, I have never seen errors like the ones you mention. Only this
"copy again". The only case in which it does NOT happen is if I run
rsync, and then run it again immediately after. If I unmount the drive
between the two runs, it does the unneeded copies again (and this only
happens for SOME, always the same, files/folders). But in no case I
have seen data loss, partition filled and so on

Marco