Re: Using the --snaptime option

[Albert Peschar <albert@peschar.net>]

> That will effectively disable the "recognize when files haven't changed"
> functionality, which will force Tarsnap to re-read files which it might
> otherwise have not bothered to re-read.

That's the hint I needed to understand how it works.

Daniel, if I am not mistaken, the idea is to flag those files that were
modified around the time of snapshot creation as modified. Normally
files with the same modification time, size and path are assumed not to
have changed. And as Colin explained earlier, this can lead to a race
condition where files that were modified twice in the same second will
not be stored correctly.

The --newer-than option does not do the same thing. It's like a
--assume-modified-if-newer-than option.

On Thu, 23 Jan 2014 08:32:14 -0800
Colin Percival <cperciva@tarsnap.com> wrote:

> On 01/23/14 08:31, Albert Peschar wrote:
> > Thanks Nick, your snippet is very helpful.
> > 
> >> Point it at anything with a modification time <= when the snapshot was
> >> created.  Obviously anything inside the snapshot will have this property;
> >> as will a file you create prior to creating the snapshot.
> > 
> > Colin, thanks for your explanation. But I'm definitely misunderstanding
> > something here: if I specify a file that was last modified 10 years
> > ago, how does that help you?
> 
> That will effectively disable the "recognize when files haven't changed"
> functionality, which will force Tarsnap to re-read files which it might
> otherwise have not bothered to re-read.
> 
> -- 
> Colin Percival
> Security Officer Emeritus, FreeBSD | The power to serve
> Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid