Removing data based on a policy when the attacker had the opportunity to
add data to your repository comes with some considerations. This is
added to the 060_forget.rst documentation.
That document is also updated to reflect that restic now considers
the current system time while running "forget".
References to the security considerations section are added:
- In `restic forget --help`
- In the threat model (design.rst)
- In the (030) setup section where an append-only setup is referenced
A reference is also to be added to the `rest-server` readme's
append-only paragraph (see my fork).
This commit also resolves a typo (amount->number for countable noun),
changes a password length recommendation into the metric that
actually matters when creating passwords (entropy) since I was editing
these doc files anyway, and updates the outdated copyright year in
`conf.py`.
Some wording in 060_forget (line 21..22) was changed to clarify what
"forget" and "prune" do, to try and avoid the apparent misconception
that "forget" does not remove any data.
Allow keeping hourly/daily/weekly/monthly/yearly snapshots for a given time period.
This adds the following flags/parameters to restic forget:
--keep-within-hourly duration
--keep-within-daily duration
--keep-within-weekly duration
--keep-within-monthly duration
--keep-within-yearly duration
Includes following changes:
- Add tests for --keep-within-hourly (and friends)
- Add documentation for --keep-within-hourly (and friends)
- Add changelog for --keep-within-hourly (and friends)
Add a callback to the PruneOptions struct which calculates the number of
bytes allowed to be unused after prune is done. This way, the logic is
closer to the option parsing code.
Also, add an explicit option `unlimited` for the use case when storage
does not matter but bandwidth and time do. Internally, this sets the
maximum number of unused bytes to MaxUint64.
Rework the documentation slightly so that no more "packs" are
mentioned and it talks about "files" instead.
Make it clear in the documentation that the percentage given to
`--max-unused` is relative to the whole repository size after pruning is
done. If specified, it must be below 100%, otherwise the repository
would contain 100% of unused data, which is pointless.
I had a hard time coming up with the correct formula to calculate the
maximum number of unused bytes based on the number of used bytes. For a
fraction `p` (0 ≤ p < 1), a repo with `u` bytes used, and the number of
unused bytes `x` the following holds:
x ≤ p * (u+x)
⇔ x ≤ p*u + p*x
⇔ x - p*x ≤ p*u
⇔ x * (1-p) ≤ p*u
⇔ x ≤ p/(1-p) * u
I went pretty loud with this, but I think the performance is bad enough
that it's really worth highlighting, especially since it locks the index
during the prune.
This commit refactors the documentation according to my proposal in #1273
and the discussion I had with fd0 on IRC.
The bits from the manual that I could not immediately put into the new
structure are contained in manual_rest.rst Anything else is still there,
nothing has been deleted.
I changed the heading markup to follow the convention used in Python’s
Style Guide for documentation, this convention is explained in a comment
at the top of every file.
I also added a paragraph on installing restic on Debian.
