Ensuring deduplication for copied snapshots

Different repositories usually have different parameters for splitting larger files into smaller chunks. When copying snapshots between arbitrary repository, deduplication between snapshots from the source and destination repository doesn’t work unless the repositories share the same parameters, the so-called chunker parameters.

rustic enforces identical chunker parameters - if you try to copy to a repository with different chunker parameter, you get an error like

cannot copy to repository with different chunker parameter (re-chunking not implemented)!

Note: Currently it is not possible to change the chunker parameters of existing repositories (re-chunking is not yet implemented).

To create a repository with identical chunker parameters to a source repository, don’t initialize the target repository, but instead run the first copy command with the --init option. This option initializes non-existing repositories with the correct chunker parameter:

rustic copy --init [SNAPSHOTS]

Note: The target repositories must be defined in the config file.