Re: [Duplicity-talk] --skip-same-content: Option to skip files whose content hasn't changed

[Elifarley Callado Coelho Cruz]

I've registered a blueprint for this at
https://blueprints.launchpad.net/duplicity/+spec/skip-same-content

On Fri, Nov 25, 2011 at 12:04, Elifarley Callado Coelho Cruz
<address@hidden> wrote:
> Hi Nate,
>
> The point of having a switch like '--skip-same-content' is to suppress
> the recording of changed mtimes when the file content hasn't changed.
> In some situations, it's not really important to track changes to
> mtimes, so why keep recording them?
>
> This will also help with the problem described at
> https://bugs.launchpad.net/duplicity/+bug/768481 (Don't write new
> incremental set if nothing changed).
>
> Here's an excerpt:
>
> ---
> For example, a few days ago I needed to restore three small files from
> a small backup set that hadn't changed in years. But to do so,
> Duplicity had to download probably over a hundred incremental sets in
> which nothing changed. This took a LONG time! It's especially slow
> since, judging from Duplicity's verbose output, it downloads one file
> at a time--the latency between commands adds up quickly (I'm ignorant
> about SFTP: is there no way to request more than one file at a time?).
> Restoring less than 20 KB of data took over 10 minutes because of all
> the empty incremental sets that had to be downloaded.
> ---
>
> - Elifarley
>
> ---
>
> Re: [Duplicity-talk] --skip-same-content: Option to skip files whose con
>
> From:    Nate Eldredge
> Subject:         Re: [Duplicity-talk] --skip-same-content: Option to skip
> files whose content hasn't changed
> Date:    Thu, 24 Nov 2011 16:46:10 -0500 (EST)
> On Thu, 24 Nov 2011, Elifarley Callado Coelho Cruz wrote:
>
> It would be nice to have an option to skip files which had their
> modification time changed without any changes to their content.
>
> Thanks to the rdiff algorithm, this effectively already happens.
> Duplicity only backs up the changes relative to the previous version
> of the file. If the data has not changed, it won't be backed up again.
> The file will still be entered in the backup (and the new mtime
> recorded), but no data will be stored and the size of the backup won't
> increase significantly. Try it and see!
>
> --
>
> Nate Eldredge
> address@hidden
>



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Elifarley Cruz

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