From: lew.pitcher@digitalfreehold.ca   
      
   On Fri, 20 Sep 2024 06:47:13 -0400, bad sector wrote:   
      
   > Speaking of backups using rsync, I just did one and as usual I checked   
   > the file sums to validate the results. In dolphin 'properties' I ended   
   > up with ONE folder showing a discrepancy i.e. correct number of files   
   > but total size being different.   
   >   
   > source 6.1 GiB (6,595,100,080)   
   > target 6.1 GiB (6,595,108,272)   
      
   This is not a definitive answer, but it is likely that rsync   
   is expanding sparse files on you.   
      
   To explain, you may have source files with "holes" in them;   
   files in which the data is scattered across the file with   
   empty space (nothing written) between blocks.   
      
   When /writing/ such a file, the system does not count the   
   size of the "holes" in the file space allocation.   
   When /reading/ such a file, the system substitutes a block   
   of binary zero for each "hole" being read.   
      
   rsync effectively reads the source file and writes the   
   target file. If it reads a sparse file, it reads blocks   
   of binary zero, When it writes the target, it writes   
   that block of binary zero (unless you specify the -S   
   flag), and the system counts that block not as a "hole",   
   but as data that needs space allocated to it. In this   
   way, /some/ files can become bigger when backed up by   
   rsync.   
      
   THIS MAY NOT BE YOUR SITUATION.   
      
   > The other dozen or so folders were all exact matches.   
   >   
   > Doing   
   > # perl -le 'map { $sum += -s } @ARGV; print $sum' -- *   
   >   
   > produced 6552446982 for both so sigh of relief.   
      
   Can you explain the difference between perl's result   
   (6552446982) and the either of the sizes reported by   
   rsync (6595100080 and/or 6595108272)?   
      
   > I understand that disk usage is not the same as sum of file sizes but   
   > WHY is du being used in dolphin properties dolphin being a FILE mangler?   
   > If I want disk usage I might just click kdf instead.   
      
      
      
      
   --   
   Lew Pitcher   
   "In Skills We Trust"   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)