Re: [Duplicity-talk] Questions

[edgar . soldin]

On 08.01.2016 13:15, wighawag wrote:
> Hi,
> 
> (sorry for the potential double post)
> 
> New to duplicity and this looks like a cool project. I am planning to use
> it for backing up to blackblaze b2 storage which duplicity now support.
> 
> I have 3 questions :
> 
> - Does duplicity do global deduplication like zbackup (http://zbackup.org/)
> ?
> (in that case changing filename, moving... does not affect deduplication)


no

> - Does duplicity ever change or delete files  on the repo or does it only
> append like zbackup does ? zbackup list it as a feature : "Repository
> consists of immutable files. No existing files are ever modified"

same. when a file is deleted, a marker is added but the file is still in the 
older volumes.

> - In case of b2 support (or other dumb remote) how much transfer is
> performed ?
> I suppose duplicity need to download the full archive in order to perform
> its deduplication logic, or can it be smarter ?

no dedup.

as a rule of thumb
- verify and restore download a complete chain
- all other operations manage to work with the manifest files (to eg. know what 
to incrementally append), which are usually caches locally

..ede/duply.net