Does rsync detect file corruption?

[Matthias Schniedermeyer]

On 22.05.2009 13:43, Daniel Carrera wrote:
> Hello,
>
> Suppose that every day cron runs this:
>
> rsync -a --times --delete $HOME /my/backups/dir/latest
>
>
> In general, rsync will only update a file if it has been modified. Now,  
> imagine that one of the files becomes corrupted in the backup directory,  
>  but the timestamp hasn't changed. Will rsync detect this?
>
> I am using rsync in a backup solution which could be summarized to:
>
> cd /my/external/disk/backups
> rsync -a --times --delete $HOME latest
> cp -al latest $TODAYS_DATE
>
>
> So, if a file never changes, I just end up with a lot of hard links  
> pointing to the same block of data. That's meant to make the backup  
> space efficient. But if that block of data gets corrupted, all my  
> "backups" for that file are gone. And I'm concerned that if that  
> happens, rsync will just merrily go along ignoring this file because the  
> timestamp says that the file hasn't been modified so it doesn't need to  
> be updated.

Exactly.

But you can (periodically) add "-c", then rsync while checksum the whole 
content of all files.

But IF you have (or suspect) such type of corrution, you have have an 
even greater problem: Your hardware is crap.




Bis denn

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