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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?

Jeff Schaller
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supermario
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    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 06 '15 at 10:42
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    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. – Axel Bregnsbo Nov 10 '16 at 12:29
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    I just found the -c option. It skips existing files based on a checksum, instead of modification time or size. – haheute Mar 01 '18 at 13:34

5 Answers5

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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.)

HongboZhu
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Chris Down
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    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 02:34
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    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 09:05
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    --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 07:41
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    @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) – Jonathan Komar Apr 21 '17 at 08:24
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    So you need --ignore-existing and -r (recursive). -v (verbose) is nice to have too :-) – DutchUncle Feb 04 '18 at 18:57
  • Not sure why I needed to do this but it worked. In the past, I've only had to throw the -a flag to execute an incremental copy......Possibly because my destination partition was not ext3/4? it was exfat. – Lon Kaut Oct 25 '19 at 15:29
  • If you use --ignore-existing, does rsync report the files that were not copied? – basZero Aug 10 '22 at 11:52
  • Is there an easy way to get a list of files that were not copied with this option? – Kvothe Sep 04 '23 at 10:42
69

The issue might be caused by different user/group IDs on source and target servers. My case was similar, having all files transferred instead of only the modified/new ones. The solution was to use parameters -t (instead of -a), and -P (equivalent to --partial --progress):

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

or shorter (thanks @Manngo);

rsync -hvrPt <source> <target>

This transfers only new files, and files already existing but modified. Parameter -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. Therefore with -a all my source and target files were always regarded as "different".

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
t0r0X
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The problem you describe is probably because you are missing the trailing / on the source directory. As a result, rsync will copy all the files twice: the first time to /foo/bar and the second time to /foo/bar/bar. Thereafter it will efficiently copy updates to /foo/bar/bar.

The correct command should be this:

rsync -avh -e "ssh -i /path/to/thishost-rsync-key" remoteuser@remotehost:/foo/bar/ /foo/bar
Chris Davies
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Notice that rsync --ignore-existing -raz --progress /var/www/88021064/var xx@server.tld:/usr/home/xxx/public_html/var/ will not not do anything, the way it worked for me is rsync --ignore-existing -raz --progress /var/www/88021064**/var/*** xx@server.tld:/usr/home/xxx/public_html/var/, and notice that will not update hideen files for hideen files only execute one more time /var/www/88021064/var/.[^.]*

David Bister
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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.

turgut kalfaoglu
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