Git Large File Storage (LFS)

Managing large files such as audio, video and graphics files has always been one of the shortcomings of Git. The general recommendation is to not have Git repositories larger than 1GB to preserve performance.

Git LFS tracking status

An LFS icon is shown on files tracked by Git LFS to denote if a file is stored as a blob or as an LFS pointer.

どのように動作するか

Git LFS client talks with the GitLab server over HTTPS. It uses HTTP Basic Authentication to authorize client requests. Once the request is authorized, Git LFS client receives instructions from where to fetch or where to push the large file.

GitLab server configuration

Documentation for GitLab instance administrators is under LFS administration doc.

要件

  • Git LFS is supported in GitLab starting with version 8.2
  • Git LFS must be enabled under project settings
  • Git LFS client version 1.0.1 and up

Known limitations

  • Git LFS v1 original API is not supported since it was deprecated early in LFS development
  • When SSH is set as a remote, Git LFS objects still go through HTTPS
  • Any Git LFS request will ask for HTTPS credentials to be provided so a good Git credentials store is recommended
  • Git LFS always assumes HTTPS so if you have GitLab server on HTTP you will have to add the URL to Git configuration manually (see troubleshooting)
Note: With 8.12 GitLab added LFS support to SSH. The Git LFS communication still goes over HTTP, but now the SSH client passes the correct credentials to the Git LFS client, so no action is required by the user.

Using Git LFS

Lets take a look at the workflow when you need to check large files into your Git repository with Git LFS. For example, if you want to upload a very large file and check it into your Git repository: 

git clone git@gitlab.example.com:group/project.git
git lfs install                       # initialize the Git LFS project
git lfs track "*.iso"                 # select the file extensions that you want to treat as large files

Once a certain file extension is marked for tracking as a LFS object you can use Git as usual without having to redo the command to track a file with the same extension: 

cp ~/tmp/debian.iso ./                # copy a large file into the current directory
git add .                             # add the large file to the project
git commit -am "Added Debian iso"     # commit the file meta data
git push origin master                # sync the git repo and large file to the GitLab server

Make sure that .gitattributes is tracked by Git. Otherwise Git LFS will not be working properly for people cloning the project: 

git add .gitattributes

Cloning the repository works the same as before. Git automatically detects the LFS-tracked files and clones them via HTTP. If you performed the git clone command with a SSH URL, you have to enter your GitLab credentials for HTTP authentication. 

git clone git@gitlab.example.com:group/project.git

If you already cloned the repository and you want to get the latest LFS object that are on the remote repository, such as for a branch from origin: 

git lfs fetch origin master

Make sure your files aren’t listed in .gitignore, otherwise, they will be ignored by Git thus will not be pushed to the remote repository.

Migrate an existing repo to Git LFS

Read the documentation on how to migrate an existing Git repository with Git LFS.

Removing objects from LFS

To remove objects from LFS:

  1. Use git filter-repo to remove the objects from the repository.
  2. Delete the relevant LFS lines for the objects you have removed from your .gitattributes file and commit those changes.

File Locking

GitLab 10.5 で導入されました。

The first thing to do before using File Locking is to tell Git LFS which kind of files are lockable. The following command will store PNG files in LFS and flag them as lockable: 

git lfs track "*.png" --lockable

After executing the above command a file named .gitattributes will be created or updated with the following content: 

*.png filter=lfs diff=lfs merge=lfs -text lockable

You can also register a file type as lockable without using LFS (In order to be able to lock/unlock a file you need a remote server that implements the LFS File Locking API), in order to do that you can edit the .gitattributes file manually: 

*.pdf lockable

After a file type has been registered as lockable, Git LFS will make them read-only on the file system automatically. This means you will need to lock the file before editing it.

Managing Locked Files

Once you’re ready to edit your file you need to lock it first: 

git lfs lock images/banner.png
Locked images/banner.png

This will register the file as locked in your name on the server: 

git lfs locks
images/banner.png  joe   ID:123

Once you have pushed your changes, you can unlock the file so others can also edit it: 

git lfs unlock images/banner.png

You can also unlock by ID: 

git lfs unlock --id=123

If for some reason you need to unlock a file that was not locked by you, you can use the --force flag as long as you have a maintainer access on the project: 

git lfs unlock --id=123 --force

トラブルシューティング

error: Repository or object not found

There are a couple of reasons why this error can occur:

  • You don’t have permissions to access certain LFS object

Check if you have permissions to push to the project or fetch from the project.

  • Project is not allowed to access the LFS object

LFS object you are trying to push to the project or fetch from the project is not available to the project anymore. Probably the object was removed from the server.

  • Local Git repository is using deprecated LFS API

Invalid status for <url> : 501

Git LFS will log the failures into a log file. To view this log file, while in project directory: 

git lfs logs last

If the status error 501 is shown, it is because:

  • Git LFS is not enabled in project settings. Check your project settings and enable Git LFS.

  • Git LFS support is not enabled on the GitLab server. Check with your GitLab administrator why Git LFS is not enabled on the server. See LFS administration documentation for instructions on how to enable LFS support.

  • Git LFS client version is not supported by GitLab server. Check your Git LFS version with git lfs version. Check the Git configuration of the project for traces of deprecated API with git lfs -l. If batch = false is set in the configuration, remove the line and try to update your Git LFS client. Only version 1.0.1 and newer are supported.

getsockopt: connection refused

If you push a LFS object to a project and you receive an error similar to: Post <URL>/info/lfs/objects/batch: dial tcp IP: getsockopt: connection refused, the LFS client is trying to reach GitLab through HTTPS. However, your GitLab instance is being served on HTTP.

This behavior is caused by Git LFS using HTTPS connections by default when a lfsurl is not set in the Git configuration.

To prevent this from happening, set the LFS URL in project Git configuration: 

git config --add lfs.url "http://gitlab.example.com/group/project.git/info/lfs"

Credentials are always required when pushing an object

Note: With 8.12 GitLab added LFS support to SSH. The Git LFS communication still goes over HTTP, but now the SSH client passes the correct credentials to the Git LFS client, so no action is required by the user.

Given that Git LFS uses HTTP Basic Authentication to authenticate the user pushing the LFS object on every push for every object, user HTTPS credentials are required.

By default, Git has support for remembering the credentials for each repository you use. This is described in Git credentials man pages.

For example, you can tell Git to remember the password for a period of time in which you expect to push the objects: 

git config --global credential.helper 'cache --timeout=3600'

This will remember the credentials for an hour after which Git operations will require re-authentication.

If you are using OS X you can use osxkeychain to store and encrypt your credentials. For Windows, you can use wincred or Microsoft’s Git Credential Manager for Windows.

More details about various methods of storing the user credentials can be found on Git Credential Storage documentation.

LFS objects are missing on push

GitLab checks files to detect LFS pointers on push. If LFS pointers are detected, GitLab tries to verify that those files already exist in LFS on GitLab.

Verify that LFS is installed locally and consider a manual push with git lfs push --all.

If you are storing LFS files outside of GitLab you can disable LFS on the project by setting lfs_enabled: false with the projects API.

Hosting LFS objects externally

It is possible to host LFS objects externally by setting a custom LFS URL with git config -f .lfsconfig lfs.url https://example.com/<project>.git/info/lfs.

You might choose to do this if you are using an appliance like a Sonatype Nexus to store LFS data. If you choose to use an external LFS store, GitLab will not be able to verify LFS objects which means that pushes will fail if you have GitLab LFS support enabled.

To stop push failure, LFS support can be disabled in the Project settings. This means you will lose GitLab LFS value-adds (Verifying LFS objects, UI integration for LFS).