280 lines
10 KiB
Markdown
280 lines
10 KiB
Markdown
---
|
|
stage: Create
|
|
group: Source Code
|
|
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/product/ux/technical-writing/#assignments
|
|
---
|
|
|
|
# Merge request diffs storage **(FREE SELF)**
|
|
|
|
Merge request diffs are size-limited copies of diffs associated with merge
|
|
requests. When viewing a merge request, diffs are sourced from these copies
|
|
wherever possible as a performance optimization.
|
|
|
|
By default, merge request diffs are stored in the database, in a table named
|
|
`merge_request_diff_files`. Larger installations may find this table grows too
|
|
large, in which case, switching to external storage is recommended.
|
|
|
|
Merge request diffs can be stored [on disk](#using-external-storage), or in
|
|
[object storage](#using-object-storage). In general, it
|
|
is better to store the diffs in the database than on disk. A compromise is available
|
|
that only [stores outdated diffs](#alternative-in-database-storage) outside of database.
|
|
|
|
## Using external storage
|
|
|
|
**In Omnibus installations:**
|
|
|
|
1. Edit `/etc/gitlab/gitlab.rb` and add the following line:
|
|
|
|
```ruby
|
|
gitlab_rails['external_diffs_enabled'] = true
|
|
```
|
|
|
|
1. The external diffs are stored in
|
|
`/var/opt/gitlab/gitlab-rails/shared/external-diffs`. To change the path,
|
|
for example, to `/mnt/storage/external-diffs`, edit `/etc/gitlab/gitlab.rb`
|
|
and add the following line:
|
|
|
|
```ruby
|
|
gitlab_rails['external_diffs_storage_path'] = "/mnt/storage/external-diffs"
|
|
```
|
|
|
|
1. Save the file and [reconfigure GitLab](restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
|
|
GitLab then migrates your existing merge request diffs to external storage.
|
|
|
|
**In installations from source:**
|
|
|
|
1. Edit `/home/git/gitlab/config/gitlab.yml` and add or amend the following
|
|
lines:
|
|
|
|
```yaml
|
|
external_diffs:
|
|
enabled: true
|
|
```
|
|
|
|
1. The external diffs are stored in
|
|
`/home/git/gitlab/shared/external-diffs`. To change the path, for example,
|
|
to `/mnt/storage/external-diffs`, edit `/home/git/gitlab/config/gitlab.yml`
|
|
and add or amend the following lines:
|
|
|
|
```yaml
|
|
external_diffs:
|
|
enabled: true
|
|
storage_path: /mnt/storage/external-diffs
|
|
```
|
|
|
|
1. Save the file and [restart GitLab](restart_gitlab.md#installations-from-source) for the changes to take effect.
|
|
GitLab then migrates your existing merge request diffs to external storage.
|
|
|
|
## Using object storage
|
|
|
|
WARNING:
|
|
Migrating to object storage is not reversible.
|
|
|
|
Instead of storing the external diffs on disk, we recommended the use of an object
|
|
store like AWS S3 instead. This configuration relies on valid AWS credentials to
|
|
be configured already.
|
|
|
|
**In Omnibus installations:**
|
|
|
|
1. Edit `/etc/gitlab/gitlab.rb` and add the following line:
|
|
|
|
```ruby
|
|
gitlab_rails['external_diffs_enabled'] = true
|
|
```
|
|
|
|
1. Set [object storage settings](#object-storage-settings).
|
|
1. Save the file and [reconfigure GitLab](restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
|
|
GitLab then migrates your existing merge request diffs to external storage.
|
|
|
|
**In installations from source:**
|
|
|
|
1. Edit `/home/git/gitlab/config/gitlab.yml` and add or amend the following
|
|
lines:
|
|
|
|
```yaml
|
|
external_diffs:
|
|
enabled: true
|
|
```
|
|
|
|
1. Set [object storage settings](#object-storage-settings).
|
|
1. Save the file and [restart GitLab](restart_gitlab.md#installations-from-source) for the changes to take effect.
|
|
GitLab then migrates your existing merge request diffs to external storage.
|
|
|
|
[Read more about using object storage with GitLab](object_storage.md).
|
|
|
|
### Object Storage Settings
|
|
|
|
In GitLab 13.2 and later, you should use the
|
|
[consolidated object storage settings](object_storage.md#consolidated-object-storage-configuration).
|
|
This section describes the earlier configuration format.
|
|
|
|
For source installations, these settings are nested under `external_diffs:` and
|
|
then `object_store:`. On Omnibus installations, they are prefixed by
|
|
`external_diffs_object_store_`.
|
|
|
|
| Setting | Description | Default |
|
|
|---------|-------------|---------|
|
|
| `enabled` | Enable/disable object storage | `false` |
|
|
| `remote_directory` | The bucket name where external diffs are stored| |
|
|
| `proxy_download` | Set to `true` to enable proxying all files served. Option allows to reduce egress traffic as this allows clients to download directly from remote storage instead of proxying all data | `false` |
|
|
| `connection` | Various connection options described below | |
|
|
|
|
#### S3 compatible connection settings
|
|
|
|
See [the available connection settings for different providers](object_storage.md#connection-settings).
|
|
|
|
**In Omnibus installations:**
|
|
|
|
1. Edit `/etc/gitlab/gitlab.rb` and add the following lines by replacing with
|
|
the values you want:
|
|
|
|
```ruby
|
|
gitlab_rails['external_diffs_enabled'] = true
|
|
gitlab_rails['external_diffs_object_store_enabled'] = true
|
|
gitlab_rails['external_diffs_object_store_remote_directory'] = "external-diffs"
|
|
gitlab_rails['external_diffs_object_store_connection'] = {
|
|
'provider' => 'AWS',
|
|
'region' => 'eu-central-1',
|
|
'aws_access_key_id' => 'AWS_ACCESS_KEY_ID',
|
|
'aws_secret_access_key' => 'AWS_SECRET_ACCESS_KEY'
|
|
}
|
|
```
|
|
|
|
If you are using AWS IAM profiles, omit the
|
|
AWS access key and secret access key/value pairs. For example:
|
|
|
|
```ruby
|
|
gitlab_rails['external_diffs_object_store_connection'] = {
|
|
'provider' => 'AWS',
|
|
'region' => 'eu-central-1',
|
|
'use_iam_profile' => true
|
|
}
|
|
```
|
|
|
|
1. Save the file and [reconfigure GitLab](restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
|
|
|
|
**In installations from source:**
|
|
|
|
1. Edit `/home/git/gitlab/config/gitlab.yml` and add or amend the following
|
|
lines:
|
|
|
|
```yaml
|
|
external_diffs:
|
|
enabled: true
|
|
object_store:
|
|
enabled: true
|
|
remote_directory: "external-diffs" # The bucket name
|
|
connection:
|
|
provider: AWS # Only AWS supported at the moment
|
|
aws_access_key_id: AWS_ACCESS_KEY_ID
|
|
aws_secret_access_key: AWS_SECRET_ACCESS_KEY
|
|
region: eu-central-1
|
|
```
|
|
|
|
1. Save the file and [restart GitLab](restart_gitlab.md#installations-from-source) for the changes to take effect.
|
|
|
|
## Alternative in-database storage
|
|
|
|
Enabling external diffs may reduce the performance of merge requests, as they
|
|
must be retrieved in a separate operation to other data. A compromise may be
|
|
reached by only storing outdated diffs externally, while keeping current diffs
|
|
in the database.
|
|
|
|
To enable this feature, perform the following steps:
|
|
|
|
**In Omnibus installations:**
|
|
|
|
1. Edit `/etc/gitlab/gitlab.rb` and add the following line:
|
|
|
|
```ruby
|
|
gitlab_rails['external_diffs_when'] = 'outdated'
|
|
```
|
|
|
|
1. Save the file and [reconfigure GitLab](restart_gitlab.md#omnibus-gitlab-reconfigure) for the changes to take effect.
|
|
|
|
**In installations from source:**
|
|
|
|
1. Edit `/home/git/gitlab/config/gitlab.yml` and add or amend the following
|
|
lines:
|
|
|
|
```yaml
|
|
external_diffs:
|
|
enabled: true
|
|
when: outdated
|
|
```
|
|
|
|
1. Save the file and [restart GitLab](restart_gitlab.md#installations-from-source) for the changes to take effect.
|
|
|
|
With this feature enabled, diffs are initially stored in the database, rather
|
|
than externally. They are moved to external storage after any of these
|
|
conditions become true:
|
|
|
|
- A newer version of the merge request diff exists
|
|
- The merge request was merged more than seven days ago
|
|
- The merge request was closed more than seven day ago
|
|
|
|
These rules strike a balance between space and performance by only storing
|
|
frequently-accessed diffs in the database. Diffs that are less likely to be
|
|
accessed are moved to external storage instead.
|
|
|
|
## Correcting incorrectly-migrated diffs
|
|
|
|
Versions of GitLab earlier than `v13.0.0` would incorrectly record the location
|
|
of some merge request diffs when [external diffs in object storage](#object-storage-settings)
|
|
were enabled. This mainly affected imported merge requests, and was resolved
|
|
with [this merge request](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/31005).
|
|
|
|
If you are using object storage, or have never used on-disk storage for external
|
|
diffs, the **Changes** tab for some merge requests fails to load with a 500 error,
|
|
and the exception for that error is of this form:
|
|
|
|
```plain
|
|
Errno::ENOENT (No such file or directory @ rb_sysopen - /var/opt/gitlab/gitlab-rails/shared/external-diffs/merge_request_diffs/mr-6167082/diff-8199789)
|
|
```
|
|
|
|
Then you are affected by this issue. Because it's not possible to safely determine
|
|
all these conditions automatically, we've provided a Rake task in GitLab v13.2.0
|
|
that you can run manually to correct the data:
|
|
|
|
**In Omnibus installations:**
|
|
|
|
```shell
|
|
sudo gitlab-rake gitlab:external_diffs:force_object_storage
|
|
```
|
|
|
|
**In installations from source:**
|
|
|
|
```shell
|
|
sudo -u git -H bundle exec rake gitlab:external_diffs:force_object_storage RAILS_ENV=production
|
|
```
|
|
|
|
Environment variables can be provided to modify the behavior of the task. The
|
|
available variables are:
|
|
|
|
| Name | Default value | Purpose |
|
|
| ---- | ------------- | ------- |
|
|
| `ANSI` | `true` | Use ANSI escape codes to make output more understandable |
|
|
| `BATCH_SIZE` | `1000` | Iterate through the table in batches of this size |
|
|
| `START_ID` | `nil` | If set, begin scanning at this ID |
|
|
| `END_ID` | `nil` | If set, stop scanning at this ID |
|
|
| `UPDATE_DELAY` | `1` | Number of seconds to sleep between updates |
|
|
|
|
The `START_ID` and `END_ID` variables may be used to run the update in parallel,
|
|
by assigning different processes to different parts of the table. The `BATCH`
|
|
and `UPDATE_DELAY` parameters allow the speed of the migration to be traded off
|
|
against concurrent access to the table. The `ANSI` parameter should be set to
|
|
false if your terminal does not support ANSI escape codes.
|
|
|
|
By default, `sudo` does not preserve existing environment variables. You should append them, rather than prefix them.
|
|
|
|
```shell
|
|
sudo gitlab-rake gitlab:external_diffs:force_object_storage START_ID=59946109 END_ID=59946109 UPDATE_DELAY=5
|
|
```
|
|
|
|
## Switching from external storage to object storage
|
|
|
|
Automatic migration moves diffs stored in the database, but it does not move diffs between storage types.
|
|
To switch from external storage to object storage:
|
|
|
|
1. Move files stored on local or NFS storage to object storage manually.
|
|
1. Run the Rake task in the [previous section](#correcting-incorrectly-migrated-diffs) to change their location in the database.
|