About migrations
A migration is the process of transferring data from a source location (either a GitHub.com organization or a GitHub Enterprise Server instance) to a target GitHub Enterprise Server instance. Migrations can be used to transfer your data when changing platforms or upgrading hardware on your instance.
Types of migrations
There are three types of migrations you can perform:
- A migration from a GitHub Enterprise Server instance to another GitHub Enterprise Server instance. You can migrate any number of repositories owned by any user or organization on the instance. Before performing a migration, you must have site administrator access to both instances.
- A migration from a GitHub.com organization to a GitHub Enterprise Server instance. You can migrate any number of repositories owned by the organization. Before performing a migration, you must have administrative access to the GitHub.com organization as well as site administrator access to the target instance.
- Trial runs are migrations that import data to a staging instance. These can be useful to see what would happen if a migration were applied to your GitHub Enterprise Server instance. We strongly recommend that you perform a trial run on a staging instance before importing data to your production instance.
Migrated data
In a migration, everything revolves around a repository. Most data associated with a repository can be migrated. For example, a repository within an organization will migrate the repository and the organization, as well as any users, teams, issues, and pull requests associated with the repository.
The items in the table below can be migrated with a repository. Any items not shown in the list of migrated data can not be migrated.
Note: Fork relationships do not persist after a migration.
| Data associated with a migrated repository | Notes |
|---|---|
| Users | @mentions of users are rewritten to match the target. |
| Organizations | An organization's name and details are migrated. |
| Repositories | Links to Git trees, blobs, commits, and lines are rewritten to match the target. The migrator follows a maximum of three repository redirects. |
| Wikis | All wiki data is migrated. |
| Teams | @mentions of teams are rewritten to match the target. |
| Milestones | Timestamps are preserved. |
| Project boards | Project boards associated with the repository and with the organization that owns the repository are migrated. |
| Issues | Issue references and timestamps are preserved. |
| Issue comments | Cross-references to comments are rewritten for the target instance. |
| Pull requests | Cross-references to pull requests are rewritten to match the target. Timestamps are preserved. |
| Pull request reviews | Pull request reviews and associated data are migrated. |
| Pull request review comments | Cross-references to comments are rewritten for the target instance. Timestamps are preserved. |
| Commit comments | Cross-references to comments are rewritten for the target instance. Timestamps are preserved. |
| Releases | All releases data is migrated. |
| Actions taken on pull requests or issues | All modifications to pull requests or issues, such as assigning users, renaming titles, and modifying labels are preserved, along with timestamps for each action. |
| File attachments | File attachments on issues and pull requests are migrated. You can choose to disable this as part of the migration. |
| Webhooks | Only active webhooks are migrated. |
| Repository deploy keys | Repository deploy keys are migrated. |
| Protected branches | Protected branch settings and associated data are migrated. |