rsync

[lewashby]

I have an iBasso DX50 digital music player and I have all of my music for it stored on a 128 GB micro SD card. I sync my music directory to it using the following command. rsync -a --delete SRC DEST but I've noticed some odd behavior. I thought the --delete option would only delete files and directories in the destination that were not in the source but it did something a little strange, no it didn't remove anything from my source directory. I had two directories for the same album but one of them must have been slightly different and it only had one song in it. Then after syncing one day rsync must have deleted the directory with all the songs in it and left only the one that had only one song. How does --delete work that it would have this behavior and what can I do to fix it? Thanks.

[Hiroshe]

According to info rsync:

--delete
       This tells rsync to delete extraneous files from  the  receiving
       side  (ones  that  aren’t on the sending side), but only for the
       directories that are being synchronized.  You  must  have  asked
       rsync to send the whole directory (e.g. "dir" or "dir/") without
       using a wildcard for the  directory’s  contents  (e.g.  "dir/*")
       since  the wildcard is expanded by the shell and rsync thus gets
       a request to transfer individual files, not  the  files’  parent
       directory.   Files  that are excluded from the transfer are also
       excluded from being deleted unless you use the --delete-excluded
       option  or  mark  the rules as only matching on the sending side
       (see the include/exclude modifiers in the FILTER RULES section).

       Prior to rsync 2.6.7, this option would have  no  effect  unless
       --recursive  was  enabled.  Beginning with 2.6.7, deletions will
       also occur when --dirs (-d) is enabled, but only for directories
       whose contents are being copied.

       This  option can be dangerous if used incorrectly!  It is a very
       good idea to first try a run using the --dry-run option (-n)  to
       see what files are going to be deleted.

       If the sending side detects any I/O errors, then the deletion of
       any files at the destination  will  be  automatically  disabled.
       This  is  to  prevent temporary filesystem failures (such as NFS
       errors) on the sending side from causing a massive  deletion  of
       files  on  the  destination.   You  can  override  this with the
       --ignore-errors option.

       The  --delete  option  may  be  combined   with   one   of   the
       --delete-WHEN    options    without   conflict,   as   well   as
       --delete-excluded.   However,  if  none  of  the   --delete-WHEN
       options  are  specified,  rsync  will choose the --delete-during
       algorithm  when  talking  to  rsync  3.0.0  or  newer,  and  the
       --delete-before  algorithm  when talking to an older rsync.  See
       also --delete-delay and --delete-after.

To fix it, you might be able to use some recovery software to scan the device for the missing music files. It might be easier to redownload it from the store/re-rip it from the CD.

[lewashby]

I haven't lost the files from my source DIR, it's all still there and all is still good. My issues are only in the destination DIR.

[mike_2000_17]

The set of options that I usually prefer for rsync is rsync -va --delete (local transfer) or rsync -vaz --delete (over network, "z" compresses the data to minimize the bandwidth needed).

But the thing that might have been the problem is that rsync can be a bit tricky in the way you specify the source and destination folders. You have to make sure they are written the same, down to the final slash character, i.e., like this:

rsync -vrt --delete /some/source/folder/ /some/dest/folder/

because it has happened in the past to me that a simple mistake like this:

rsync -vrt --delete /some/source/folder /some/dest/folder/

would result in ending up with a subfolder called "folder" in the destination folder (i.e. /some/dest/folder/folder). It's just something to watch out for, rsync is just a bit quirky like that. And don't use globing.

[elicro]

Because --delete means that it will sync the dest directory to be exactly like the origin directory including deleting files and directories on the dest directory which exists there but not on the origin directory.