Incremental backups with git bundle, for all branches
backup, git
Solution
(We discussed this problem with Jukka, this is the outcome.)
Preliminaries:
- Have the last backup available as `backup.bundle`
- Have a remote `backup` that points at `backup.bundle`
Making a backup:
- `git fetch backup` – just to make sure we're up to date
- `git bundle create newbackup.bundle ^backup/A ^backup/B A B C`
- This means we create a bundle that excludes all the stuff that was already in the bundle
- It's easy to generate the needed `^backup/A`-style arguments from `refs/remotes/backup/`
- Likewise the `A`-style arguments are from `refs/heads`
- copy `newbackup.bundle` to wherever you keep your backups
- replace `backup.bundle` with `newbackup.bundle` so you know where to start the next incremental backup
Recovering:
- Have a repository that is either empty or represents an old version of your repository
- For every backup file, in sequence:
- `git remote rm recovery`
- `git remote add recovery <name-of-bundle>`
- `git fetch recovery` – you need to name the remote for this to work
- Now you should have every branch available in `refs/remotes/backup`
Problem
What is the easiest way to do incremental backups of a git repository with `git bundle`? If I just wanted to backup a single branch, I could do something along these lines: ``` git bundle create foo last-backup..master git tag -f last-backup master ``` But what if I want to backup everything (including all branches)? To answer the questions in the comments: Strictly speaking, I do not need to use the usual Git bundles, as long as the solution satisfies the following properties: Each incremental backup is a single file. I can store it somewhere and subsequent incremental backups do not need to modify this file. The size of the file is approximately equal to the total size of Git commits since the previous backup. Changes in binary files are also efficiently stored. A full backup + all incremental backups since then contain everything that I need to automatically reconstruct the repository, including all branches. (As a naive example, simply constructing a tar archive with recently-changed files in the git repository fails to satisfy the second requirement if, for example, automatic garbage collection has occurred.) And ideally I would also like to have a system that is idiot-proof: - I can take virtually any full backup of my Git repository, plus all recent incremental backups, and I can simply "pull" everything from the backups and the repository will be up-to-date. In particular, it does not matter if there is a partial overlap between the full backup and incremental backups. Git bundles satisfy all this very nicely if I only need to handle one branch.