rsync - Aug 2009 - Rsync completed successfully, but files are not identical

Hi All,

I came into a strange issue running rsync on directory with ~500,000 files.
Some of the file, although with same time stamps and size on source and
destination, were different on the destination.
The destination is just a mirrored area, and the data written to it, is just the
one that comes through rsync.
Needless to mentioned, that when I remove files and synced them again it works,
or when I did the sync with checksum.

Due to the large number of files, running it with checksum is very bad options
for me.

I have few questions:

1)      Any idea how come a replicated area, has files with same time stamp and
size, but file is different than the source?
2)      Is there a way for rsync to verify, that each transferred size is
identical as the source, after the file was transferred?

Thanks in advanced,
Oren Mark


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On 16.08.2009 11:38, Mark, Oren wrote:
> Hi All,
> 
> I came into a strange issue running rsync on directory with ~500,000 files.
> Some of the file, although with same time stamps and size on source and
destination, were different on the destination.
> The destination is just a mirrored area, and the data written to it, is
just the one that comes through rsync.
> Needless to mentioned, that when I remove files and synced them again it
works, or when I did the sync with checksum.
> 
> Due to the large number of files, running it with checksum is very bad
options for me.
> 
> I have few questions:
> 
> 1)      Any idea how come a replicated area, has files with same time stamp
and size, but file is different than the source?
> 2)      Is there a way for rsync to verify, that each transferred size is
identical as the source, after the file was transferred?
My first question would be if i have a program on the source side that 
"tampers" with files and then resets the atime/mtime, as long as the 
size stays the same it's the same file for rsync.

And i faintly remember reading about an issue with mtime and mmap 
writing files. I don't remember the details, but i guess if there was an 
issue it is remedied in recent kernels.


IOW i'm quite sure the culprit isn't rsync.



Bis denn

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