rsync - Dec 2014 - Differing behaviour on consecutive runs

Hi all. I have a strange issue with sync'ing from a USB-attached ext4 
file system on one machine, to a USB-attached ext3 file system on another.

The sync works fine (a few thousand files). If I run it again straight 
away, or a few minutes later, rsync reports no action required.

But if I wait for a few hours and run it again it copies all the files 
again.

I'm trying to determine what's making it think the files are not 
up-to-date. I have all the debug flags turned on. Am I missing something 
that will let me know what rsync is thinking?

My command-line is:

rsync --info=all4 --debug=all4 -auvz --modify-window=1 ./src/dir/ 
server:path/to/dst/dir/

On the good run I see this in the output:
...
generator starting pid=3205
delta-transmission enabled
recv_generator(.,0)
recv_generator(.,1)
recv_generator(604-001-bg.jpg,2)
604-001-bg.jpg is uptodate
recv_generator(604-001-l.jpg,3)
604-001-l.jpg is uptodate
recv_generator(604-001-m.jpg,4)
604-001-m.jpg is uptodate
...

and on the later run when everything is copied again I see this:
...
generator starting pid=10544
delta-transmission enabled
recv_generator(.,0)
set modtime of . to (1282081725) Wed Aug 18 07:48:45 2010
recv_generator(.,1)
recv_generator(604-001-bg.jpg,2)
recv_generator(604-001-l.jpg,3)
recv_generator(604-001-m.jpg,4)
...

I've just noticed that "set modtime" differs between the two runs.
If I
do an ls now on that directory I get:

$ ls -ld --time-style=full-iso 604
drwxr-xr-x 2 dave dave 4096 2010-08-18 07:48:45.000000000 +1000 604

Sorry for the long post. This issue has been driving me crazy.

Dave.

On Wed 17 Dec 2014, David Jennings wrote:
> Hi all. I have a strange issue with sync'ing from a USB-attached ext4
file
> system on one machine, to a USB-attached ext3 file system on another.
> The sync works fine (a few thousand files). If I run it again straight
away,
> or a few minutes later, rsync reports no action required.
> 
> But if I wait for a few hours and run it again it copies all the files
> again.
> 
> I'm trying to determine what's making it think the files are not
up-to-date.
> I have all the debug flags turned on. Am I missing something that will let
> me know what rsync is thinking?
Use -i (or --itemize-changes), that's more helpful in determining _why_
a file is being updated.
> I've just noticed that "set modtime" differs between the two
runs. If I do
> an ls now on that directory I get:
The times of a directory are hardly useful, writing a file or renaming a
file in that directory will update the modification time of the
directory. Check file timestamps if you're trying to track something
down, but first try it with -i (and leave out all the debugging, that
might just obscure the -i output).



Paul