git-annex/doc/special_remotes/bup.mdwn

This special remote type stores file contents in a 
[bup](http://github.com/apenwarr/bup) repository. By using git-annex
in the front-end, and bup as a remote, you get an easy git-style
interface to large files, and easy backups of the file contents using git.

This is particularly well suited to collaboration on projects involving
large files, since both the git-annex and bup repositories can be
accessed like any other git repository.

See [[walkthrough/using_bup]] for usage examples.

Each individual key is stored in a bup remote using `bup split`, with
a git branch named the same as the key name. Content is retrieved from
bup using `bup join`. All other bup operations are up to you -- consider
running `bup fsck --generate` in a cron job to generate recovery blocks,
for example; or clone bup's git repository to further back it up.

## configuration

These parameters can be passed to `git annex initremote` to configure bup:

* `encryption` - Required. Either "none" to disable encryption of content
  stored in bup (ssh will still be used to transport it securely),
  or a value that can be looked up (using gpg -k) to find a gpg encryption
  key that will be given access to the remote, or "shared" which allows
  every clone of the repository to access the encrypted data (use with caution).

  Note that additional gpg keys can be given access to a remote by
  rerunning initremote with the new key id. See [[encryption]].

* `buprepo` - Required. This is passed to `bup` as the `--remote`
  to use to store data. To create the repository,`bup init` will be run.
  Example: "buprepo=example.com:/big/mybup" or "buprepo=/big/mybup"
  (To use the default `~/.bup` repository on the local host, specify "buprepo=")

Options to pass to `bup split` when sending content to bup can also
be specified, by using `git config annex.bup-split-options`. This
can be used to, for example, limit its bandwidth.

## notes

[[git-annex-shell]] does not support bup, due to the wacky way that bup
starts its server. So, to use bup, you need full shell access to the server.