There is problem of rsync with options --hard-links --inplace.

[Matthias Schniedermeyer]

On 15.02.2017 00:07, Viper wrote:
> There is the problem which I discribed here
> https://bugs.centos.org/view.php?id=12820.
> rsync does not break hard-link into destination if hard-link has be broken
> in source with option inplace.
> The problem remains in the latest version of rsync?

This is documented in the man-page.

- snip -
...
      --inplace
              This option changes how rsync transfers a file when its 
data needs to be updated: instead of the default method of creating a 
new copy of the file and moving it into place when it is complete, rsync 
instead writes the updated data directly to the destination file.

              This has several effects:

              o      Hard  links  are  not  broken.   This means the new 
data will be visible through other hard links to the destination file.  
Moreover, attempts to copy differing source files onto a multiply-linked 
destination file will result in a "tug of war" with the destination data 
changing back and forth.

...
- snip -

"--inplace" is an option where you have to know what you are doing, 
otherwise it can go horribly wrong.

Personally i rarely use "--inplace" and in the cases where i do use it i 
skip it periodicaly for exactly the reason to fix (eventual) 
hardlink-errors.
For e.g. in my daily backup-script i skip the option on fridays, this 
way hardlink errors will get fixed within a week.

If correct hardlinks are important to you, the best you can do is 
execute rsync twice. Once with --inplace and after that again without 
--inplace. If there are no changes in the meantime, the most the second 
rsync will do is fix hardlink errors.






-- 

Matthias