-H option causes unneccessary transfers

[Albert Berger]

Thanks!

On Mon, Mar 28, 2016 at 08:49:09AM -0400, Kevin Korb wrote:
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> My guess is that it is the atimes patch causing the problem.  Normally
> rsync would never say "u" in the itemized output as it is "reserved
> for future use".  Plus copying the file would change the atime.
> 
> On 03/28/2016 08:44 AM, Albert Berger wrote:
> > On Mon, Mar 28, 2016 at 08:11:07AM -0400, Kevin Korb wrote:
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> >> What does --itemize-changes say about these files?
> >> 
> >> Also, what is --atimes?  Is this the Apple modified rsync for
> >> OSX?
> >> 
> >> On 03/28/2016 07:51 AM, Albert Berger wrote:
> >>> Greetings,
> >>> 
> >>> when the daily system backup with rsync is performed, thousands
> >>> of files (e.g. from /usr directory), which are not modified
> >>> are uselessly transferrred to the backup storage every day. The
> >>> rsync command is the following:
> >>> 
> >>> rsync --update -DHAErlptgo --relative --atimes --delete-during 
> >>> ${SRCPATH} ${BACKUPDIR}
> >>> 
> >>> Quick investigation shown, that these files are hard links, and
> >>> the command option related to this behaviour is -H: without it
> >>> the unmodified files are not copied. Seemingly this situation
> >>> is described in the rsync manual:
> >>> 
> >>> "If  incremental recursion is active (see --recursive), rsync
> >>> may transfer a missing hard-linked file before it finds that
> >>> another link for that contents  exists  else‐ where  in  the
> >>> hierarchy.... One way to avoid this inefficiency  is  to
> >>> disable incremental recursion  using the --no-inc-recursive
> >>> option."
> >>> 
> >>> Adding --no-inc-recursive to the aforementioned command line 
> >>> doesn't help (are --recursive and --no-inc-recursive supposed
> >>> to be used in one option set?). And I use --recursive to copy
> >>> entire directory tree, including subdirectories. Could someone
> >>> advise please how one can prevent copying unmodified
> >>> hard-linked files?
> >>> 
> >>> Thanks, A. Berger.
> >>> 
> > 
> > As an example of copying hard-linked files, the /usr/bin contains
> > the following two hard-linked sets for two inodes:
> > 
> > inode 1: ld ld.bfd
> > 
> > inode 2: g++ i686-pc-linux-gnu-c++ i686-pc-linux-gnu-g++ c++
> > 
> > Below is the --itemized-changes output for those two sets which is
> > produced when /usr/bin doesn't have any modifications and is synced
> > with the aforementioned command to its backup copy:
> > 
> > hf......u.. /usr/bin/ld.bfd hf......u..
> > /usr/bin/i686-pc-linux-gnu-c++ hf......u..
> > /usr/bin/i686-pc-linux-gnu-g++ hf......u.. /usr/bin/g++
> > 
> > As can bee seen, one file in each set is not listed at all, and all
> > other hard-linked files are marked for updating. Is this behaviour
> > normal?
> > 
> > --atimes is an option for preserving access times. This option is
> > added by patching rsync source with a patch from
> > rsync-patches-3.1.1.tar.gz file from rsync download page.
> > 
> > The system is ArchLinux, kernel 4.4.5.
> > 
> > 
> > Regards, A.Berger.
> > 
> 
> - -- 
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> 	Kevin Korb			Phone:    (407) 252-6853
> 	Systems Administrator		Internet:
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