rsync - Jan 2008 - Feature Request: Options to limit --one-file-system at the source or destination.

Greetings.


  Currently, the --one-file-system applies to both the source and
  destination and this is a problem.

  In my source, I have a symlink pointing to a directory on another
  device which I would like to have copied.  I thus use
  --copy-unsafe-links.

  I also use --delete.  This is dangerous because if there is a bug in
  my script, I would not like the destination to become suddenly / and
  deletion occurs on mounted network drives (granted, the machine would
  be toast, but the damage would be limited to the machine; not the
  corporate network).

  If I make use of --one-file-system, the symlink at the source gets
  ignored.  So I need a --one-file-system option that applies only to
  the destination, probably named something like
  --one-file-system-at-destination.

  Could that be easily implemented?  The following two options would be
  nice:

  --one-file-system-at-source
    # Limit to one file system at the source.

  --one-file-system-at-destination
    # Limit to one file system at the destination.


Best regards,
Hans Deragon
--
Consultant en informatique/Software Consultant
Deragon Informatique inc.
http://www.deragon.biz        Open source (contribution):
mailto://hans@deragon.biz     http://autopoweroff.sourceforge.net

On Tue, 2008-01-15 at 13:21 -0500, Hans Deragon wrote:
>   Currently, the --one-file-system applies to both the source and
>   destination and this is a problem.
> 
>   In my source, I have a symlink pointing to a directory on another
>   device which I would like to have copied.  I thus use
>   --copy-unsafe-links.
> 
>   I also use --delete.  This is dangerous because if there is a bug in
>   my script, I would not like the destination to become suddenly / and
>   deletion occurs on mounted network drives (granted, the machine would
>   be toast, but the damage would be limited to the machine; not the
>   corporate network).
> 
>   If I make use of --one-file-system, the symlink at the source gets
>   ignored.  So I need a --one-file-system option that applies only to
>   the destination, probably named something like
>   --one-file-system-at-destination.
> 
>   Could that be easily implemented?  The following two options would be
>   nice:
> 
>   --one-file-system-at-source
>     # Limit to one file system at the source.
> 
>   --one-file-system-at-destination
>     # Limit to one file system at the destination.
This is a good feature request and would be easy to implement.

However, if the source contains only a small, fixed set of
cross-filesystem symlinks that you want to follow, a quicker solution
would be to use --relative and provide for each such symlink an
additional source argument that reaches through it, starting a new
--one-file-system traversal at its target.  This approach also avoids
the need for --copy-unsafe-links.  For example, if you want to copy
~/src to ~/dest and have rsync follow a symlink ~/src/extrafiles
-> /tmp/extrafiles to obtain additional source files, you would run:

rsync -r --relative --one-file-system \
	~/src/./ ~/src/./extrafiles/ ~/dest/

Another approach is to use protect filters instead of --one-file-system
as a precaution against undesired deletions.

Matt

Matt McCutchen wrote:
> On Tue, 2008-01-15 at 13:21 -0500, Hans Deragon wrote:
>>   Currently, the --one-file-system applies to both the source and
>>   destination and this is a problem.
>>
>>   In my source, I have a symlink pointing to a directory on another
>>   device which I would like to have copied.  I thus use
>>   --copy-unsafe-links.
>>
>>   I also use --delete.  This is dangerous because if there is a bug in
>>   my script, I would not like the destination to become suddenly / and
>>   deletion occurs on mounted network drives (granted, the machine would
>>   be toast, but the damage would be limited to the machine; not the
>>   corporate network).
>>
>>   If I make use of --one-file-system, the symlink at the source gets
>>   ignored.  So I need a --one-file-system option that applies only to
>>   the destination, probably named something like
>>   --one-file-system-at-destination.
>>
>>   Could that be easily implemented?  The following two options would be
>>   nice:
>>
>>   --one-file-system-at-source
>>     # Limit to one file system at the source.
>>
>>   --one-file-system-at-destination
>>     # Limit to one file system at the destination.
> 
> This is a good feature request and would be easy to implement.
> 
> However, if the source contains only a small, fixed set of
> cross-filesystem symlinks that you want to follow, a quicker solution
> would be to use --relative and provide for each such symlink an
> additional source argument that reaches through it, starting a new
> --one-file-system traversal at its target.  This approach also avoids
> the need for --copy-unsafe-links.  For example, if you want to copy
> ~/src to ~/dest and have rsync follow a symlink ~/src/extrafiles
> -> /tmp/extrafiles to obtain additional source files, you would run:
> 
> rsync -r --relative --one-file-system \
> 	~/src/./ ~/src/./extrafiles/ ~/dest/
> 
> Another approach is to use protect filters instead of --one-file-system
> as a precaution against undesired deletions.
> 
> Matt
Greetings Matt.


  Mmm.  None of the solutions you presented to me would be satisfying.
For the moment, a got ride of the symlinks at the source by recopying
the files from the other device (have a script to update them).  Not
ideal, but it does the job.


Thank you for the quick response.
Hans Deragon
--
Consultant en informatique/Software Consultant
Deragon Informatique inc.
http://www.deragon.biz        Open source (contribution):
mailto://hans@deragon.biz     http://autopoweroff.sourceforge.net