Re: [rdiff-backup-users] backup misses files with older date

[Paul Bijnens]

On 2009-01-09 17:01, Chris Wilson wrote:
> On Wed, 7 Jan 2009, bt101 wrote:
>
> > I installed rdiff-backup and used it for a few days.  I was eager to 
> > see how it would handle a small change to a large (2G) truecrypt 
> > file.  I added a small file into the truecrypt file and then performed 
> > a backup. To my surprise, the truecrypt file was completely missed 
> > from the backup.  I then looked at the modify date of the truecrypt 
> > file and it was old.  It seems truecrypt will preserve the modify date 
> > (there's a setting to change it if you wish).
>
> This is an annoying and pointless misfeature of truecrypt. It causes 
> problems for other backup software as well. Turn it off if you want to 
> back up truecrypt volumes, and complain to the developers of truecrypt. 
> Timestamps exist for a reason and subverting them by default is 
> dangerous and pointless. I'm fairly sure that the ctime will change 
> whenever the volume is accessed as the timestamp is reset, and therefore 
> changing the mtime provides only the tiniest shred of obscurity.
>
> > Be that as it may, am I to understand that backup programs will 
> > completely miss files that NEED to be backed-up, simply because their 
> > dates are old?  Do they not do a checksum or something?
>
> Almost all backup software will honour timestamps. They exist for a 
> reason. Software that changes the data without changing the timestamp is 
> broken.

GNUtar includes a file in the incremental backup if the mtime OR ctime
changes.   Does rdiff-backup check only the mtime and ignores the ctime?

--
Paul Bijnens
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