Re: [Duplicity-talk] how much metadata does duplicity store between runs

[Kenneth Loafman]

Sitaram Chamarty wrote:
> Hello all,
> 
> I'm currently unable to install duplicity on my Mandriva system
> without jumping through quite a few hoops, so I thought I'd just ask
> instead of doing all that to find the answer to my question.

If the instructions are bad / not enough / wrong, please let me know.

> I know that librsync needs only a set of checksums for the old file,
> and the full new file.  Since duplicity can work with almost any type
> of remote file system, I imagine it is not dependent on something
> running "on the other side" to generate those checksums (unlike plain
> rsync, for instance).  Therefore I imagine that, when one run is done,
> it stores the checksums required for older versions locally, to be
> used as inputs for the next run.

That's what the signature files are about.  Hashes are stored for each
block in a file.  That way the incremental backup can store only changed
blocks.

> Is my understanding correct, and if so how much metadata (as a very
> rough fraction of the actual files being backed up) is stored.  Very
> approximate numbers or guesses are also fine -- I'm mainly looking to
> see if I've understood this at all :-)

Well below 5% of the total backup would be metadata.

...Ken

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