Rsync completed successfully, but files are not identical

Matthias Schniedermeyer ms at citd.de
Sun Aug 16 03:20:00 MDT 2009


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

-- 
Real Programmers consider "what you see is what you get" to be just as 
bad a concept in Text Editors as it is in women. No, the Real Programmer
wants a "you asked for it, you got it" text editor -- complicated, 
cryptic, powerful, unforgiving, dangerous.



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