path: root/doc/administration/raketasks/check.md

---
stage: Enablement
group: Distribution
info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
---

# Integrity check Rake task **(FREE SELF)**

GitLab provides Rake tasks to check the integrity of various components.

## Repository integrity

Even though Git is very resilient and tries to prevent data integrity issues,
there are times when things go wrong. The following Rake tasks intend to
help GitLab administrators diagnose problem repositories so they can be fixed.

There are 3 things that are checked to determine integrity.

1. Git repository file system check ([`git fsck`](https://git-scm.com/docs/git-fsck)).
   This step verifies the connectivity and validity of objects in the repository.
1. Check for `config.lock` in the repository directory.
1. Check for any branch/references lock files in `refs/heads`.

It's important to note that the existence of `config.lock` or reference locks
alone do not necessarily indicate a problem. Lock files are routinely created
and removed as Git and GitLab perform operations on the repository. They serve
to prevent data integrity issues. However, if a Git operation is interrupted these
locks may not be cleaned up properly.

The following symptoms may indicate a problem with repository integrity. If users
experience these symptoms you may use the Rake tasks described below to determine
exactly which repositories are causing the trouble.

- Receiving an error when trying to push code - `remote: error: cannot lock ref`
- A 500 error when viewing the GitLab dashboard or when accessing a specific project.

### Check all GitLab repositories

This task loops through all repositories on the GitLab server and runs the
integrity check described previously.

**Omnibus Installation**

```shell
sudo gitlab-rake gitlab:git:fsck
```

**Source Installation**

```shell
sudo -u git -H bundle exec rake gitlab:git:fsck RAILS_ENV=production
```

## Checksum of repository refs

One Git repository can be compared to another by checksumming all refs of each
repository. If both repositories have the same refs, and if both repositories
pass an integrity check, then we can be confident that both repositories are the
same.

For example, this can be used to compare a backup of a repository against the
source repository.

### Check all GitLab repositories

This task loops through all repositories on the GitLab server and outputs
checksums in the format `<PROJECT ID>,<CHECKSUM>`.

- If a repository doesn't exist, the project ID will have a blank checksum.
- If a repository exists but is empty, the output checksum is `0000000000000000000000000000000000000000`.
- Projects which don't exist are skipped.

**Omnibus Installation**

```shell
sudo gitlab-rake gitlab:git:checksum_projects
```

**Source Installation**

```shell
sudo -u git -H bundle exec rake gitlab:git:checksum_projects RAILS_ENV=production
```

For example, if:

- Project with ID#2 doesn't exist, it will be skipped.
- Project with ID#4 doesn't have a repository, its checksum will be blank.
- Project with ID#5 has an empty repository, its checksum will be `0000000000000000000000000000000000000000`.

The output would then look something like:

```plaintext
1,cfa3f06ba235c13df0bb28e079bcea62c5848af2
3,3f3fb58a8106230e3a6c6b48adc2712fb3b6ef87
4,
5,0000000000000000000000000000000000000000
6,6c6b48adc2712fb3b6ef87cfa3f06ba235c13df0
```

### Check specific GitLab repositories

Optionally, specific project IDs can be checksummed by setting an environment
variable `CHECKSUM_PROJECT_IDS` with a list of comma-separated integers, for example:

```shell
CHECKSUM_PROJECT_IDS="1,3" sudo gitlab-rake gitlab:git:checksum_projects
```

## Uploaded files integrity

Various types of files can be uploaded to a GitLab installation by users.
These integrity checks can detect missing files. Additionally, for locally
stored files, checksums are generated and stored in the database upon upload,
and these checks verify them against current files.

Currently, integrity checks are supported for the following types of file:

- CI artifacts (Available from version 10.7.0)
- LFS objects (Available from version 10.6.0)
- User uploads (Available from version 10.6.0)

**Omnibus Installation**

```shell
sudo gitlab-rake gitlab:artifacts:check
sudo gitlab-rake gitlab:lfs:check
sudo gitlab-rake gitlab:uploads:check
```

**Source Installation**

```shell
sudo -u git -H bundle exec rake gitlab:artifacts:check RAILS_ENV=production
sudo -u git -H bundle exec rake gitlab:lfs:check RAILS_ENV=production
sudo -u git -H bundle exec rake gitlab:uploads:check RAILS_ENV=production
```

These tasks also accept some environment variables which you can use to override
certain values:

Variable  | Type    | Description
--------- | ------- | -----------
`BATCH`   | integer | Specifies the size of the batch. Defaults to 200.
`ID_FROM` | integer | Specifies the ID to start from, inclusive of the value.
`ID_TO`   | integer | Specifies the ID value to end at, inclusive of the value.
`VERBOSE` | boolean | Causes failures to be listed individually, rather than being summarized.

```shell
sudo gitlab-rake gitlab:artifacts:check BATCH=100 ID_FROM=50 ID_TO=250
sudo gitlab-rake gitlab:lfs:check BATCH=100 ID_FROM=50 ID_TO=250
sudo gitlab-rake gitlab:uploads:check BATCH=100 ID_FROM=50 ID_TO=250
```

Example output:

```shell
$ sudo gitlab-rake gitlab:uploads:check
Checking integrity of Uploads
- 1..1350: Failures: 0
- 1351..2743: Failures: 0
- 2745..4349: Failures: 2
- 4357..5762: Failures: 1
- 5764..7140: Failures: 2
- 7142..8651: Failures: 0
- 8653..10134: Failures: 0
- 10135..11773: Failures: 0
- 11777..13315: Failures: 0
Done!
```

Example verbose output:

```shell
$ sudo gitlab-rake gitlab:uploads:check VERBOSE=1
Checking integrity of Uploads
- 1..1350: Failures: 0
- 1351..2743: Failures: 0
- 2745..4349: Failures: 2
  - Upload: 3573: #<Errno::ENOENT: No such file or directory @ rb_sysopen - /opt/gitlab/embedded/service/gitlab-rails/public/uploads/user-foo/project-bar/7a77cc52947bfe188adeff42f890bb77/image.png>
  - Upload: 3580: #<Errno::ENOENT: No such file or directory @ rb_sysopen - /opt/gitlab/embedded/service/gitlab-rails/public/uploads/user-foo/project-bar/2840ba1ba3b2ecfa3478a7b161375f8a/pug.png>
- 4357..5762: Failures: 1
  - Upload: 4636: #<Google::Apis::ServerError: Server error>
- 5764..7140: Failures: 2
  - Upload: 5812: #<NoMethodError: undefined method `hashed_storage?' for nil:NilClass>
  - Upload: 5837: #<NoMethodError: undefined method `hashed_storage?' for nil:NilClass>
- 7142..8651: Failures: 0
- 8653..10134: Failures: 0
- 10135..11773: Failures: 0
- 11777..13315: Failures: 0
Done!
```

## LDAP check

The LDAP check Rake task tests the bind DN and password credentials
(if configured) and lists a sample of LDAP users. This task is also
executed as part of the `gitlab:check` task, but can run independently.
See [LDAP Rake Tasks - LDAP Check](ldap.md#check) for details.

## Troubleshooting

The following are solutions to problems you might discover using the Rake tasks documented
above.

### Dangling commits

`gitlab:git:fsck` can find dangling commits. To fix them, try
[manually triggering housekeeping](../housekeeping.md#manual-housekeeping)
for the affected project(s).

If the issue persists, try triggering `gc` via the
[Rails Console](../operations/rails_console.md#starting-a-rails-console-session):

```ruby
p = Project.find_by_path("project-name")
Repositories::HousekeepingService.new(p, :gc).execute
```

### Delete references to missing remote uploads

`gitlab-rake gitlab:uploads:check VERBOSE=1` detects remote objects that do not exist because they were
deleted externally but their references still exist in the GitLab database.

Example output with error message:

```shell
$ sudo gitlab-rake gitlab:uploads:check VERBOSE=1
Checking integrity of Uploads
- 100..434: Failures: 2
- Upload: 100: Remote object does not exist
- Upload: 101: Remote object does not exist
Done!
```

To delete these references to remote uploads that were deleted externally, open the [GitLab Rails Console](../operations/rails_console.md#starting-a-rails-console-session) and run:

```ruby
uploads_deleted=0
Upload.find_each do |upload|
  next if upload.retrieve_uploader.file.exists?
  uploads_deleted=uploads_deleted + 1
  p upload                            ### allow verification before destroy
  # p upload.destroy!                 ### uncomment to actually destroy
end
p "#{uploads_deleted} remote objects were destroyed."
```

### Delete references to missing LFS objects

If `gitlab-rake gitlab:lfs:check VERBOSE=1` detects LFS objects that exist in the database
but not on disk, [follow the procedure in the LFS documentation](../../topics/git/lfs/index.md#missing-lfs-objects)
to remove the database entries.