Troubleshooting Geo synchronization and verification errors

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If you notice replication or verification failures in Admin > Geo > Sites or the Sync status Rake task, you can try to resolve the failures with the following general steps:

Geo automatically retries failures. If the failures are new and few in number, or if you suspect the root cause is already resolved, then you can wait to see if the failures go away.
If failures were present for a long time, then many retries have already occurred, and the interval between automatic retries has increased to up to 4 hours depending on the type of failure. If you suspect the root cause is already resolved, you can manually retry replication or verification to avoid the wait.
If the failures persist, use the following sections to try to resolve them.

Manually retry replication or verification

In Rails console in a secondary Geo site, you can:

Manually resync and reverify individual components
Manually resync and reverify multiple components

Resync and reverify individual components

You can force a resync and reverify individual items for all component types managed by the self-service framework using the UI. On the secondary site, visit Admin > Geo > Replication.

However, if this doesn't work, you can perform the same action using the Rails console. The following sections describe how to use internal application commands in the Rails console to cause replication or verification for individual records synchronously or asynchronously.

Obtaining a Replicator instance

Commands that change data can cause damage if not run correctly or under the right conditions. Always run commands in a test environment first and have a backup instance ready to restore.

Before you can perform any sync or verify operations, you need to obtain a Replicator instance.

First, start a Rails console session in a primary or secondary site, depending on what you want to do.

Primary site:

You can checksum a resource

Secondary site:

You can sync a resource
You can checksum a resource and verify that checksum against the primary site's checksum

Next, run one of the following snippets to get a Replicator instance.

Given a model record's ID

Replace 123 with the actual ID.
Replace Packages::PackageFile with any of the Geo data type Model classes.

model_record = Packages::PackageFile.find_by(id: 123)
replicator = model_record.replicator

Given a registry record's ID

Replace 432 with the actual ID. Note that a Registry record may or may not have the same ID value as the Model record that it tracks.
Replace Geo::PackageFileRegistry with any of the Geo Registry classes.

In a secondary Geo site:

registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator

Given an error message in a Registry record's `last_sync_failure`

Replace Geo::PackageFileRegistry with any of the Geo Registry classes.
Replace error message here with the actual error message.

registry = Geo::PackageFileRegistry.find_by("last_sync_failure LIKE '%error message here%'")
replicator = registry.replicator

Given an error message in a Registry record's `verification_failure`

Replace Geo::PackageFileRegistry with any of the Geo Registry classes.
Replace error message here with the actual error message.

registry = Geo::PackageFileRegistry.find_by("verification_failure LIKE '%error message here%'")
replicator = registry.replicator

Performing operations with a Replicator instance

After you have a Replicator instance stored in a replicator variable, you can perform many operations:

Sync in the console

This snippet only works in a secondary site.

This executes the sync code synchronously in the console, so you can observe how long it takes to sync a resource, or view a full error backtrace.

replicator.sync

Optionally, make the log level of the console more verbose than the configured log level, and then perform a sync:

Rails.logger.level = :debug

Checksum or verify in the console

This snippet works in any primary or secondary site.

In a primary site, it checksums the resource and stores the result in the main GitLab database. In a secondary site, it checksums the resource, compares it against the checksum in the main GitLab database (generated by the primary site), and stores the result in the Geo Tracking database.

This executes the checksum and verification code synchronously in the console, so you can observe how long it takes, or view a full error backtrace.

replicator.verify

Sync in a Sidekiq job

This snippet only works in a secondary site.

It enqueues a job for Sidekiq to perform a sync of the resource.

replicator.enqueue_sync

Verify in a Sidekiq job

This snippet works in any primary or secondary site.

It enqueues a job for Sidekiq to perform a checksum or verify of the resource.

replicator.verify_async

Get a model record

This snippet works in any primary or secondary site.

replicator.model_record

Get a registry record

This snippet only works in a secondary site because registry tables are stored in the Geo Tracking DB.

registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```0

#### Geo data type Model classes

A Geo data type is a specific class of data that is required by one or more GitLab features to store
relevant data and is replicated by Geo to secondary sites.

- **Blob types:**
  - `Ci::JobArtifact`
  - `Ci::PipelineArtifact`
  - `Ci::SecureFile`
  - `LfsObject`
  - `MergeRequestDiff`
  - `Packages::PackageFile`
  - `PagesDeployment`
  - `Terraform::StateVersion`
  - `Upload`
  - `DependencyProxy::Manifest`
  - `DependencyProxy::Blob`
- **Git Repository types:**
  - `DesignManagement::Repository`
  - `ProjectRepository`
  - `ProjectWikiRepository`
  - `SnippetRepository`
  - `GroupWikiRepository`
- **Other types:**
  - `ContainerRepository`

The main kinds of classes are Registry, Model, and Replicator. If you have an instance of one of
these classes, you can get the others. The Registry and Model mostly manage PostgreSQL DB state. The
Replicator knows how to replicate or verify the non-PostgreSQL data (file/Git repository/Container
repository).

#### Geo Registry classes

In the context of GitLab Geo, a **registry record** refers to registry tables in
the Geo tracking database. Each record tracks a single replicable in the main
GitLab database, such as an LFS file, or a project Git repository. The Rails
models that correspond to Geo registry tables that can be queried are:

- **Blob types:**
  - `Geo::CiSecureFileRegistry`
  - `Geo::DependencyProxyBlobRegistry`
  - `Geo::DependencyProxyManifestRegistry`
  - `Geo::JobArtifactRegistry`
  - `Geo::LfsObjectRegistry`
  - `Geo::MergeRequestDiffRegistry`
  - `Geo::PackageFileRegistry`
  - `Geo::PagesDeploymentRegistry`
  - `Geo::PipelineArtifactRegistry`
  - `Geo::ProjectWikiRepositoryRegistry`
  - `Geo::SnippetRepositoryRegistry`
  - `Geo::TerraformStateVersionRegistry`
  - `Geo::UploadRegistry`
- **Git Repository types:**
  - `Geo::DesignManagementRepositoryRegistry`
  - `Geo::ProjectRepositoryRegistry`
  - `Geo::ProjectWikiRepositoryRegistry`
  - `Geo::SnippetRepositoryRegistry`
  - `Geo::GroupWikiRepositoryRegistry`
- **Other types:**
  - `Geo::ContainerRepositoryRegistry`

### Resync and reverify multiple components

#### Version history

- Bulk resync and reverify [added](https://gitlab.com/gitlab-org/gitlab/-/issues/364729) in GitLab 16.5.

Commands that change data can cause damage if not run correctly or under the right conditions.
Always run commands in a test environment first and have a backup instance ready to restore.

The following sections describe how to use internal application commands in the
[Rails console](../../../operations/rails_console.md#starting-a-rails-console-session) to cause bulk
replication or verification.

#### Resync all resources of one component

You can schedule a full resync of all resources of one component from the UI:

1. On the left sidebar, at the bottom, select **Admin**.
1. Select **Geo > Sites**.
1. Under **Replication details**, select the desired component.
1. Select **Resync all**.

Alternatively,
[start a Rails console session](../../../operations/rails_console.md#starting-a-rails-console-session)
**on the secondary Geo site** to gather more information, or execute these operations manually using
the snippets below.

Commands that change data can cause damage if not run correctly or under the right conditions.
Always run commands in a test environment first and have a backup instance ready to restore.

##### Sync all resources of one component that failed to sync

The following script:

- Loops over all failed repositories.
- Displays the Geo sync and verification metadata, including the reasons for the last failure.
- Attempts to resync the repository.
- Reports back if a failure occurs, and why.
- Might take some time to complete. Each repository check must complete
  before reporting back the result. If your session times out, take measures
  to allow the process to continue running such as starting a `screen` session,
  or running it using [Rails runner](../../../operations/rails_console.md#using-the-rails-runner)
  and `nohup`.

```ruby
registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```1

#### Reverify one component on all sites

If the **primary** site's checksums are in question, then you need to make the **primary** site recalculate checksums. A "full re-verification" is then achieved, because after each checksum is recalculated on a **primary** site, events are generated which propagate to all **secondary** sites, causing them to recalculate their checksums and compare values. Any mismatch marks the registry as `sync failed`, which causes sync retries to be scheduled.

The UI does not provide a button to do a "full re-verification". You can simulate this by setting your **primary** site's `Re-verification interval` to 1 (day) in **Admin > Geo > Nodes > Edit**. The **primary** site will then recalculate the checksum of any resource that has been checksummed more than 1 day ago.

Optionally, you can do this manually:

1. SSH into a GitLab Rails node in the **primary** site.
1. Open the [Rails console](../../../operations/rails_console.md#starting-a-rails-console-session).
1. Replacing `Upload` with any of the [Geo data type Model classes](#geo-data-type-model-classes),
   mark all resources as `pending verification`:

   ```ruby
   Upload.verification_state_table_class.each_batch do |relation|
     relation.update_all(verification_state: 0)
   end

Reverify all resources that failed to checksum on the primary site

The system automatically reverifies all resources that failed to checksum on the primary site, but it uses a progressive backoff scheme to avoid an excessive volume of failures.

Optionally, for example if you've completed an attempted intervention, you can manually trigger reverification sooner:

SSH into a GitLab Rails node in the primary site.
Open the Rails console.

Replacing Upload with any of the Geo data type Model classes, mark all resources as pending verification:

Upload.verification_state_table_class.where(verification_state: 3).each_batch do |relation|
  relation.update_all(verification_state: 0)
end

Reverify one component on one secondary site

If you believe the primary site checksums are correct, you can schedule a reverification of one component on one secondary site from the UI:

On the left sidebar, at the bottom, select Admin.
Select Geo > Sites.
Under Replication details, select the desired component.
Select Reverify all.

Errors

Failed verification of Uploads on the primary Geo site

If verification of some uploads is failing on the primary Geo site with verification_checksum = nil and with verification_failure containing Error during verification: undefined method `underscore' for NilClass:Class or The model which owns this Upload is missing., this is due to orphaned Uploads. The parent record owning the Upload (the upload's "model") has somehow been deleted, but the Upload record still exists. This is usually due to a bug in the application, introduced by implementing bulk delete of the "model" while forgetting to bulk delete its associated Upload records. These verification failures are therefore not failures to verify, rather, the errors are a result of bad data in Postgres.

You can find these errors in the geo.log file on the primary Geo site.

To confirm that model records are missing, you can run a Rake task on the primary Geo site:

registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```2

You can delete these Upload records on the primary Geo site to get rid of these failures by running the following script from the [Rails console](../../../operations/rails_console.md):

```ruby
registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```3

The above script defines a method named `delete_orphaned_uploads` which you can call like this to do a dry run:

```ruby
registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```4

And to actually delete the orphaned upload rows:

```ruby
registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```5

### Message: `"Error during verification","error":"File is not checksummable"`

If you encounter these errors in your primary site `geo.log`, they're also reflected in the UI under **Admin > Geo > Sites**. To remove those errors, you can identify the particular blob that generates the message so that you can inspect it.

1. In a Puma or Sidekiq node in the primary site, [open a Rails console](../../../operations/rails_console.md#starting-a-rails-console-session).
1. Run the following snippet to find the affected artifacts containing the `File is not checksummable` message:

The example provided below uses `JobArtifact` blob type; however, the same solution applies to any blob type that Geo uses.

```ruby
registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```6

If you determine that the affected files need to be recovered then you can explore these options (non-exhaustive) to recover the missing files:

- Check if the secondary site has the object and manually copy them to the primary.
- Look through old backups and manually copy the object back into the primary site.
- Spot check some to try to determine that it's probably fine to destroy the records, for example, if they are all very old artifacts, then maybe they are not critical data.

Often, these kinds of errors happen when a file is checksummed by Geo, and then goes missing from the primary site. After you identify the affected files, you should check the projects that the files belong to from the UI to decide if it's acceptable to delete the file reference. If so, you can destroy the references with the following irreversible snippet:

```ruby
registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```7

### Error: `Error syncing repository: 13:fatal: could not read Username`

The `last_sync_failure` error
`Error syncing repository: 13:fatal: could not read Username for 'https://gitlab.example.com': terminal prompts disabled`
indicates that JWT authentication is failing during a Geo clone or fetch request.
See [Geo (development) > Authentication](../../../../development/geo.md#authentication) for more context.

First, check that system clocks are synced. Run the [Health check Rake task](common.md#health-check-rake-task), or
manually check that `date`, on all Sidekiq nodes on the secondary site and all Puma nodes on the primary site, are the
same.

If system clocks are synced, then the JWT token may be expiring while Git fetch is performing calculations between its
two separate HTTP requests. See [issue 464101](https://gitlab.com/gitlab-org/gitlab/-/issues/464101), which existed in
all GitLab versions until it was fixed in GitLab 17.1.0, 17.0.5, and 16.11.7.

To validate if you are experiencing this issue:

1. Monkey patch the code in a [Rails console](../../../operations/rails_console.md#starting-a-rails-console-session) to increase the validity period of the token from 1 minute to 10 minutes. Run
   this in Rails console on the secondary site:

   ```ruby
   module Gitlab; module Geo; class BaseRequest
     private
     def geo_auth_token(message)
       signed_data = Gitlab::Geo::SignedData.new(geo_node: requesting_node, validity_period: 10.minutes).sign_and_encode_data(message)

       "#{GITLAB_GEO_AUTH_TOKEN_TYPE} #{signed_data}"
     end
   end;end;end

In the same Rails console, resync an affected project:

Project.find_by_full_path('<mygroup/mysubgroup/myproject>').replicator.resync

Look at the sync state:

Project.find_by_full_path('<mygroup/mysubgroup/myproject>').replicator.registry

If last_sync_failure no longer includes the error fatal: could not read Username, then you are affected by this issue. The state should now be 2, meaning "synced". If so, then you should upgrade to a GitLab version with the fix. You may also wish to upvote or comment on issue 466681 which would have reduced the severity of this issue.

To workaround the issue, you must hot-patch all Sidekiq nodes in the secondary site to extend the JWT expiration time:

Edit /opt/gitlab/embedded/service/gitlab-rails/ee/lib/gitlab/geo/signed_data.rb.

Find Gitlab::Geo::SignedData.new(geo_node: requesting_node) and add , validity_period: 10.minutes to it:

- Gitlab::Geo::SignedData.new(geo_node: requesting_node)
+ Gitlab::Geo::SignedData.new(geo_node: requesting_node, validity_period: 10.minutes)

Restart Sidekiq:
```
sudo gitlab-ctl restart sidekiq
```
Unless you upgrade to a version containing the fix, you would have to repeat this workaround after every GitLab upgrade.

Error: `fetch remote: signal: terminated: context deadline exceeded` at exactly 3 hours

If Git fetch fails at exactly three hours while syncing a Git repository:

Edit /etc/gitlab/gitlab.rb to increase the Git timeout from the default of 10800 seconds:
```
# Git timeout in seconds
gitlab_rails['gitlab_shell_git_timeout'] = 21600
```
Reconfigure GitLab:
```
sudo gitlab-ctl reconfigure
```

Error `Failed to open TCP connection to localhost:5000` on secondary when configuring registry replication

You may face the following error when configuring container registry replication on the secondary site:

registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```8

It happens if the container registry is not enabled on the secondary site. To fix it, check that the container registry
is [enabled on the secondary site](../../../packages/container_registry.md#enable-the-container-registry). Note that if [Let’s Encrypt integration is disabled](https://docs.gitlab.com/omnibus/settings/ssl/#configure-https-manually), container registry is disabled as well, and you must [configure it manually](../../../packages/container_registry.md#configure-container-registry-under-its-own-domain).

### Message: `Synchronization failed - Error syncing repository`

If large repositories are affected by this problem,
their resync may take a long time and cause significant load on your Geo sites,
storage and network systems.

The following error message indicates a consistency check error when syncing the repository:

```ruby
registry_record = Geo::PackageFileRegistry.find_by(id: 432)
replicator = registry_record.replicator
```9

Several issues can trigger this error. For example, problems with email addresses:

```ruby
registry = Geo::PackageFileRegistry.find_by("last_sync_failure LIKE '%error message here%'")
replicator = registry.replicator
```0

Another issue that can trigger this error is `object <SHA>: hasDotgit: contains '.git'`. Check the specific errors because you might have more than one problem across all
your repositories.

A second synchronization error can also be caused by repository check issues:

```ruby
registry = Geo::PackageFileRegistry.find_by("last_sync_failure LIKE '%error message here%'")
replicator = registry.replicator
```1

These errors can be observed by [immediately syncing all failed repositories](#sync-all-resources-of-one-component-that-failed-to-sync).

Removing the malformed objects causing consistency errors involves rewriting the repository history, which is usually not an option.

To ignore these consistency checks, reconfigure Gitaly **on the secondary Geo sites** to ignore these `git fsck` issues.
The following configuration example:

- [Uses the new configuration structure](../../../../update/versions/gitlab_16_changes.md#gitaly-configuration-structure-change) required from GitLab 16.0.
- Ignores five common check failures.

[The Gitaly documentation has more details](../../../gitaly/consistency_checks.md)
about other Git check failures and earlier versions of GitLab.

```ruby
registry = Geo::PackageFileRegistry.find_by("last_sync_failure LIKE '%error message here%'")
replicator = registry.replicator
```2

GitLab 16.1 and later [include an enhancement](https://gitlab.com/gitlab-org/gitaly/-/merge_requests/5879) that might resolve some of these issues.

[Gitaly issue 5625](https://gitlab.com/gitlab-org/gitaly/-/issues/5625) proposes to ensure that Geo replicates repositories even if the source repository contains
problematic commits.

### Related error `does not appear to be a git repository`

You can also get the error message `Synchronization failed - Error syncing repository` along with the following log messages.
This error indicates that the expected Geo remote is not present in the `.git/config` file
of a repository on the secondary Geo site's file system:

```ruby
registry = Geo::PackageFileRegistry.find_by("last_sync_failure LIKE '%error message here%'")
replicator = registry.replicator
```3

To solve this:

1. Sign in on the web interface for the secondary Geo site.

1. Back up [the `.git` folder](../../../repository_storage_paths.md#translate-hashed-storage-paths).

1. Optional. [Spot-check](../../../logs/log_parsing.md#find-all-projects-affected-by-a-fatal-git-problem)
   a few of those IDs whether they indeed correspond
   to a project with known Geo replication failures.
   Use `fatal: 'geo'` as the `grep` term and the following API call:

   ```shell
   curl --request GET --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/projects/<first_failed_geo_sync_ID>"

Enter the Rails console and run:

failed_project_registries = Geo::ProjectRepositoryRegistry.failed

if failed_project_registries.any?
  puts "Found #{failed_project_registries.count} failed project repository registry entries:"

  failed_project_registries.each do |registry|
    puts "ID: #{registry.id}, Project ID: #{registry.project_id}, Last Sync Failure: '#{registry.last_sync_failure}'"
  end
else
  puts "No failed project repository registry entries found."
end

Run the following commands to execute a new sync for each project:

failed_project_registries.each do |registry|
  registry.replicator.sync
  puts "Sync initiated for registry ID: #{registry.id}, Project ID: #{registry.project_id}"
end

Failures during backfill

During a backfill, failures are scheduled to be retried at the end of the backfill queue, therefore these failures only clear up after the backfill completes.

Message: `unexpected disconnect while reading sideband packet`

Unstable networking conditions can cause Gitaly to fail when trying to fetch large repository data from the primary site. Those conditions can result in this error:

registry = Geo::PackageFileRegistry.find_by("last_sync_failure LIKE '%error message here%'")
replicator = registry.replicator
```4

This error is more likely to happen if a repository has to be
replicated from scratch between sites.

Geo retries several times, but if the transmission is consistently interrupted
by network hiccups, an alternative method such as `rsync` can be used to circumvent `git` and
create the initial copy of any repository that fails to be replicated by Geo.

We recommend transferring each failing repository individually and checking for consistency
after each transfer. Follow the [single target `rsync` instructions](../../../operations/moving_repositories.md#single-rsync-to-another-server)
to transfer each affected repository from the primary to the secondary site.

## Find repository check failures in a Geo secondary site

All repositories data types have been migrated to the Geo Self-Service Framework in GitLab 16.3. There is an [issue to implement this functionality back in the Geo Self-Service Framework](https://gitlab.com/gitlab-org/gitlab/-/issues/426659).

For GitLab 16.2 and earlier:

When [enabled for all projects](../../../repository_checks.md#enable-repository-checks-for-all-projects), [Repository checks](../../../repository_checks.md) are also performed on Geo secondary sites. The metadata is stored in the Geo tracking database.

Repository check failures on a Geo secondary site do not necessarily imply a replication problem. Here is a general approach to resolve these failures.

1. Find affected repositories as mentioned below, as well as their [logged errors](../../../repository_checks.md#what-to-do-if-a-check-failed).
1. Try to diagnose specific `git fsck` errors. The range of possible errors is wide, try putting them into search engines.
1. Test typical functions of the affected repositories. Pull from the secondary, view the files.
1. Check if the primary site's copy of the repository has an identical `git fsck` error. If you are planning a failover, then consider prioritizing that the secondary site has the same information that the primary site has. Ensure you have a backup of the primary, and follow [planned failover guidelines](../../disaster_recovery/planned_failover.md).
1. Push to the primary and check if the change gets replicated to the secondary site.
1. If replication is not automatically working, try to manually sync the repository.

[Start a Rails console session](../../../operations/rails_console.md#starting-a-rails-console-session)
to enact the following, basic troubleshooting steps.

Commands that change data can cause damage if not run correctly or under the right conditions. Always run commands in a test environment first and have a backup instance ready to restore.

### Get the number of repositories that failed the repository check

```ruby
registry = Geo::PackageFileRegistry.find_by("last_sync_failure LIKE '%error message here%'")
replicator = registry.replicator
```5

### Find the repositories that failed the repository check

```ruby
registry = Geo::PackageFileRegistry.find_by("last_sync_failure LIKE '%error message here%'")
replicator = registry.replicator
```6

## Resetting Geo **secondary** site replication

If you get a **secondary** site in a broken state and want to reset the replication state,
to start again from scratch, there are a few steps that can help you:

1. Stop Sidekiq and the Geo Log Cursor.

   It's possible to make Sidekiq stop gracefully, but making it stop getting new jobs and
   wait until the current jobs to finish processing.

   You need to send a **SIGTSTP** kill signal for the first phase and them a **SIGTERM**
   when all jobs have finished. Otherwise just use the `gitlab-ctl stop` commands.

   ```shell
   gitlab-ctl status sidekiq
   # run: sidekiq: (pid 10180) <- this is the PID you will use
   kill -TSTP 10180 # change to the correct PID

   gitlab-ctl stop sidekiq
   gitlab-ctl stop geo-logcursor

You can watch the Sidekiq logs to know when Sidekiq jobs processing has finished:

gitlab-ctl tail sidekiq

Clear Gitaly/Gitaly Cluster data.

Gitaly

   mv /var/opt/gitlab/git-data/repositories /var/opt/gitlab/git-data/repositories.old
   sudo gitlab-ctl reconfigure

Gitaly Cluster

Optional. Disable the Praefect internal load balancer.

Stop Praefect on each Praefect server:
```
sudo gitlab-ctl stop praefect
```

Reset the Praefect database:

sudo /opt/gitlab/embedded/bin/psql -U praefect -d template1 -h localhost -c "DROP DATABASE praefect_production WITH (FORCE);"
sudo /opt/gitlab/embedded/bin/psql -U praefect -d template1 -h localhost -c "CREATE DATABASE praefect_production WITH OWNER=praefect ENCODING=UTF8;"

Rename/delete repository data from each Gitaly node:

sudo mv /var/opt/gitlab/git-data/repositories /var/opt/gitlab/git-data/repositories.old
sudo gitlab-ctl reconfigure

On your Praefect deploy node run reconfigure to set up the database:
```
sudo gitlab-ctl reconfigure
```
Start Praefect on each Praefect server:
```
sudo gitlab-ctl start praefect
```
Optional. If you disabled it, reactivate the Praefect internal load balancer.

You may want to remove the /var/opt/gitlab/git-data/repositories.old in the future as soon as you confirmed that you don't need it anymore, to save disk space.

Optional. Rename other data folders and create new ones.

You may still have files on the secondary site that have been removed from the primary site, but this removal has not been reflected. If you skip this step, these files are not removed from the Geo secondary site.

Any uploaded content (like file attachments, avatars, or LFS objects) is stored in a subfolder in one of these paths:
- /var/opt/gitlab/gitlab-rails/shared
- /var/opt/gitlab/gitlab-rails/uploads
To rename all of them:
```
gitlab-ctl stop

mv /var/opt/gitlab/gitlab-rails/shared /var/opt/gitlab/gitlab-rails/shared.old
mkdir -p /var/opt/gitlab/gitlab-rails/shared

mv /var/opt/gitlab/gitlab-rails/uploads /var/opt/gitlab/gitlab-rails/uploads.old
mkdir -p /var/opt/gitlab/gitlab-rails/uploads

gitlab-ctl start postgresql
gitlab-ctl start geo-postgresql
```
Reconfigure to recreate the folders and make sure permissions and ownership are correct:
```
gitlab-ctl reconfigure
```

Reset the Tracking Database.

If you skipped the optional step 3, be sure both geo-postgresql and postgresql services are running.

gitlab-rake db:drop:geo DISABLE_DATABASE_ENVIRONMENT_CHECK=1   # on a secondary app node
gitlab-ctl reconfigure     # on the tracking database node
gitlab-rake db:migrate:geo # on a secondary app node

Restart previously stopped services.
```
gitlab-ctl start
```

Troubleshooting Geo synchronization and verification errors

Manually retry replication or verification

Resync and reverify individual components

Obtaining a Replicator instance

Given a model record's ID

Given a registry record's ID

Given an error message in a Registry record's last_sync_failure

Given an error message in a Registry record's verification_failure

Performing operations with a Replicator instance

Sync in the console

Checksum or verify in the console

Sync in a Sidekiq job

Verify in a Sidekiq job

Get a model record

Get a registry record

Reverify all resources that failed to checksum on the primary site

Reverify one component on one secondary site

Errors

Failed verification of Uploads on the primary Geo site

Error: fetch remote: signal: terminated: context deadline exceeded at exactly 3 hours

Error Failed to open TCP connection to localhost:5000 on secondary when configuring registry replication

Failures during backfill

Message: unexpected disconnect while reading sideband packet

Gitaly

Gitaly Cluster

Given an error message in a Registry record's `last_sync_failure`

Given an error message in a Registry record's `verification_failure`

Error: `fetch remote: signal: terminated: context deadline exceeded` at exactly 3 hours

Error `Failed to open TCP connection to localhost:5000` on secondary when configuring registry replication

Message: `unexpected disconnect while reading sideband packet`