git-annex/doc/upgrades.mdwn
Joey Hess 3cd3757236
annex.dotfiles
The git add behavior changes could be avoided if it turns out to be
really annoying, but then it would need to behave the old way when
annex.dotfiles=false and the new way when annex.dotfiles=true. I'd
rather not have the config option result in such divergent behavior as
`git annex add .` skipping a dotfile (old) vs adding to annex (new).

Note that the assistant always adds dotfiles to the annex.
This is surprising, but not new behavior. Might be worth making it also
honor annex.dotfiles, but I wonder if perhaps some user somewhere uses
it and keeps large files in a directory that happens to begin with a
dot. Since dotfiles and dotdirs are a unix culture thing, and the
assistant users may not be part of that culture, it seems best to keep
its current behavior for now.
2019-12-26 16:33:39 -04:00

203 lines
7.5 KiB
Markdown

[[!toc levels=3]]
# Software upgrades
Upgrading the code base of git-annex will be done differently depending on
your [[install]] method. For most distribution-based packages, it is
handled by the package management software.
For the standalone distribution, the [[git-annex-webapp]](1) will ask the
user for confirmation when it detects a new version. Once that is
confirmed, or if `annex.autoupgrade` is enabled (see the [[git-annex]](1)
manpage) the assistant will start the upgrade. The upgrade process is
fairly simple: the assistant will move the `git-annex.linux` directory out
of the way and replace it with the new version, then re-execute itself. It
therefore needs write access to the parent directory of the
`git-annex.linux` directory.
Note that "upgrading" from a distribution-based package to the
[[install/Linux_standalone/]] version may cause weird problems, as an
unexpected version of git-annex (e.g. the old one from packages) may be
ran.
# Repository upgrades
Occasionally improvements are made to how git-annex stores its data,
that require an upgrade process to convert repositories made with an older
version to be used by a newer version. It's annoying, it should happen
rarely, but sometimes, it's worth it.
There's a commitment that git-annex will always support upgrades from all
past versions. After all, you may have offline drives from an earlier
git-annex, and might want to use them with a newer git-annex.
git-annex will notice if it is run in a repository that
needs an upgrade, and either automatically upgrade it or
refuse to do anything. To upgrade, use the "git annex upgrade" command.
To prevent automatic upgrades in a repository, run:
`git config annex.autoupgraderepository false`
The upgrade process is guaranteed to be conflict-free. Unless you
already have git conflicts in your repository or between repositories.
Upgrading a repository with conflicts is not recommended; resolve the
conflicts first before upgrading git-annex.
The upgrade process needs to write to the repository. If the original
repository cannot be written to (due to eg being on readonly media),
the upgrade would need to be run in a copy of the repository.
The upgrade events, so far:
## v7 -> v8 (git-annex version 8.x)
v7 repositories are automatically upgraded to v8.
Some sqlite databases that git-annex uses were changed in v8 and have to be
re-populated.
Any incremental fscks that were started in v7 won't resume where they left
off in v8, but will instead begin again from the first file.
An interrupted export that was started in v7 won't resume where it left off
after upgrade to v8; files will be re-uploaded to the export remote.
After the upgrade, git-annex will in some situations have to do extra
work while it finishes populating the new databases. After this one-time
speed cost, git-annex's speed will improve when using the new and improved
databases.
Also, there are some behavior changes around adding dotfiles. While before
git-annex add skipped adding dotfiles when operating on whole directories,
and added dotfiles that were explicitly listed to the annex, it now adds
dotfiles to git by default, unless annex.dotfiles is set to true.
## v6 -> v7 (git-annex version 7.x)
v6 repositories are automatically upgraded to v7.
The only difference between v6 and v7 is that some additional git hooks
were added in v7. See below for details about what's new in v6/v7.
## v5 -> v6 (git-annex version 6.x)
v5 repositories are automatically upgraded to v6.
A v6 git-annex repository can have some files locked while other files are
unlocked, and all git and git-annex commands can be used on both locked and
unlocked files. It's a good idea to make sure that all users of the
repository have upgraded git-annex and upgraded their repositories
to the new version before starting to use this feature, since old
versions of git-annex will ignore the new unlocked files.
Direct mode repositories are upgraded to instead use the new
[[adjusted branches feature|git-annex-adjust]], which transparently unlocks
all locked files in the local repository.
The behavior of some commands changes in an upgraded repository:
* `When `annex.largefiles` is configured, git add` will add matching
files to the annex, rather than adding them directly to the git
repository.
* `git annex unlock` and `git annex lock` change how the pointer to
the annexed content is stored in git. If you commit the change,
that will impact all clones of the repository. This means all clones of the
repository will need to run at least v6 to correctly synchronise.
There is also a new `annex.thin` setting, which makes unlocked files in v6
repositories be hard linked to their content, instead of a copy. This saves
disk space but means any modification of an unlocked file will lose the
local (and possibly only) copy of the old version. This is automatically
enabled when upgrading a direct mode repository, since direct mode made the
same tradeoff.
See [[tips/unlocked_files/]] for more details about locked files and thin
mode.
## v4 -> v5 (git-annex version 5.x)
The upgrade from v4 to v5 is handled
automatically, and only affects [[direct mode]] repositories.
This upgrade involves changing direct mode repositories to operate with
core.bare=true.
## v3 -> v4 (git-annex version 4.x)
v4 was only used for [[direct_mode]], to ensure that a version of git-annex
that understands direct mode was used with a direct mode repository.
## v2 -> v3 (git-annex version 3.x)
Involved moving the .git-annex/ directory into a separate git-annex branch.
After this upgrade, you should make sure you include the git-annex branch
when git pushing and pulling.
### tips for this upgrade
This upgrade is easier (and faster!) than the previous upgrades.
You don't need to upgrade every repository at once; it's sufficient
to upgrade each repository only when you next use it.
Example upgrade process:
cd localrepo
git pull
git annex upgrade
git commit -m "upgrade v2 to v3"
git gc
## v1 -> v2 (git-annex version 0.20110316)
Involved adding hashing to .git/annex/ and changing the names of all keys.
Symlinks changed.
Also, hashing was added to location log files in .git-annex/.
And .gitattributes needed to have another line added to it.
Previously, files added to the SHA [[backends]] did not have their file
size tracked, while files added to the WORM backend did. Files added to
the SHA backends after the conversion will have their file size tracked,
and that information will be used by git-annex for disk free space checking.
To ensure that information is available for all your annexed files, see
[[upgrades/SHA_size]].
### tips for this upgrade
This upgrade can tend to take a while, if you have a lot of files.
Each clone of a repository should be individually upgraded.
Until a repository's remotes have been upgraded, git-annex
will refuse to communicate with them.
Start by upgrading one repository, and then you can commit
the changes git-annex staged during upgrade, and push them out to other
repositories. And then upgrade those other repositories. Doing it this
way avoids git-annex doing some duplicate work during the upgrade.
Example upgrade process:
cd localrepo
git pull
git annex upgrade
git commit -m "upgrade v1 to v2"
git push
ssh remote
cd remoterepo
git pull
git annex upgrade
...
## v0 -> v1 (git-annex version 0.04)
Involved a reorganisation of the layout of .git/annex/. Symlinks changed.
Handled more or less transparently, although git-annex was just 2 weeks
old at the time, and had few users other than Joey.
Before doing this upgrade, set annex.version:
git config annex.version 0