rsync compares all files again and again

Kevin Korb kmk at
Fri Oct 14 12:39:48 MDT 2011

Hash: SHA1

Correct.  rsync doesn't pay attention to ctime as it can't set ctime to
arbitrary values.

On 10/14/11 14:37, Elliot Wilen wrote:
> Thanks, somehow I'd convinced myself that when I did a -vv, I could see larger files taking longer to "compare" than smaller files. But this was probably when actual syncs of those files were going on. Retest shows you're right, of course.
> Frank's idea seems to be valid, though: why not compare the mtimes of directories and skip comparing the mtimes & sizes of files in those directories which haven't changed?
> Note 1: It looks like you'd still have to compare subdirs even if their parent dirs don't have a change in mtime.
> Note 2: Frank mentioned ctime but I think mtime is what you need to look at.
> Elliot Wilen
> Network Administrator/Postmaster
> MPR Associates, Inc.
> 2150 Shattuck Ave., Suite 800
> Berkeley, CA 94704
> Phone: (510) 849-4942
> Fax: (510) 849-0794
> On Oct 14, 2011, at 11:08 AM, Kevin Korb wrote:
>> Hash: SHA1
>> Rsync doesn't compare every file over and over unless you tell it to or
>> you don't tell it to sync timestamps (which is part of -a).  Otherwise
>> it compares the file size and mtime.  If those are the same it assumes
>> the contents are the same.
>> The only reason you are getting a listing of all files is that you are
>> using -v twice.  If you just use -iv you will only see files that rsync
>> is doing something with and why rsync is doing something with them.

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