I am trying to set up rsync to synchronize my main web server to the remote server by adding newly generated file to the latter.

Here is the command that I use:

rsync -avh --update -e "ssh -i /path/to/thishost-rsync-key" remoteuser@remotehost:/foo/bar /foo/bar

But it seems that the web server actually transfers all files despite the '--update' flag. I have tried different flag combinations (e.g. omitting '-a' and using'-uv' instead) but none helped. How can I modify the rsync command to send out only newly added files?

  • 2
    If you want to sync files to the remote server, shouldn't it come last? i.e. rsync /foo/bar remoteuser@remotehost:/foo/bar
    – ostrokach
    Jun 28 '15 at 13:07
  • You could be interested by this webpage. Also, be careful with the filesystem. If the server's filesystem doesn't support all that -a option implies (owner, group, perms, ...) it should be the cause of our issue.
    – ppr
    Jul 6 '15 at 10:42
  • 2
    None of the answers solves the problem where the local files were not fully copied to the remote destination, and you only want to rsync newer files. Nov 10 '16 at 12:29
  • 2
    I just found the -c option. It skips existing files based on a checksum, instead of modification time or size.
    – haheute
    Mar 1 '18 at 13:34

From man rsync:

--ignore-existing       skip updating files that exist on receiver

--update does something slightly different, which is probably why you are getting unexpected results (see man rsync):

This forces rsync to skip any files which exist on the destination and have a modified time that is newer than the source file. (If an existing destination file has a modification time equal to the source file's, it will be updated if the sizes are different.)

  • 2
    Well actually I tried the command with '--ignore-existing' instead of '--update'. It finished fast but does not put the new files into remote host. Any ideas? Thanks
    – supermario
    Mar 12 '13 at 2:34
  • 18
    Man pages suck (that's right I went there), case in point, does --ignore-existing mean don't transfer files which exist on receiver, or don't transfer files if some file/folder with the same name exists on the receiver?
    – puk
    Nov 20 '13 at 9:05
  • 8
    --update does skip files when the mtimes are identical (which is not what the wording implies). I tested this. I believe the wording would be better understood if it said "only source files which are newer than destination will be copied".
    – Octopus
    Nov 28 '15 at 7:41
  • 5
    @Octopus "only source files which are newer than destination will be copied" ...or source files that have same modification time as their destination file counterparts, but have different sizes. I think that is an important point. (Chris already covered that, thanks) Apr 21 '17 at 8:24
  • So you need --ignore-existing and -r (recursive). -v (verbose) is nice to have too :-)
    – DutchUncle
    Feb 4 '18 at 18:57

In my case I had similar issues, having all files transferred instead of only the modified/new ones. I solved this by using parameters -t (instead of -a), and -P (equivalent to --partial --progress):

rsync -h -v -r -P -t source target

This transfers only new files, and files already existing but modified: -a does too much, like user and group ID sync, which in my case can not work as I have different users and groups on my source and target systems.

The parameters in detail:

  • -h: human readable numbers
  • -v: verbose
  • -r: recurse into directories
  • -P: --partial (keep partially transferred files) +
            --progress (show progress during transfer)
  • -t: preserve modification times
  • 4
    +1 for '-a does too much` (indeed -rlptgoD, so permission get not flattended, groups and owner preserved –not my typical play-safe backup...) Oct 18 '18 at 11:39
  • Worked for me. I prefer to type rsync -hvrPt for convenience.
    – Manngo
    Jan 19 '20 at 6:01

From my experience with rsync, a 1TB partition copying is too large to be efficient. It takes rsync forever to process it. Instead, do it by subdirectories. That is, run rsync for each main subdirectory. It goes a lot faster if it doesn't have to juggle tens of thousands of files.

  • 4
    Maybe you ran out of memory and your system started swapping? Feb 26 '16 at 21:24

To copy only new files you can use following command:

rsync -v -a --ignore-existing /backup/ /site/

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