Add latest changes from gitlab-org/gitlab@14-0-stable-eev14.0.0-rc42

4 files changed, 311 insertions, 126 deletions

diff --git a/doc/administration/gitaly/configure_gitaly.md b/doc/administration/gitaly/configure_gitaly.md
index c9b6fd4c510..0b22df5a115 100644
--- a/doc/administration/gitaly/configure_gitaly.md
+++ b/doc/administration/gitaly/configure_gitaly.md
@@ -82,7 +82,7 @@ The following list depicts the network architecture of Gitaly:
 - Gitaly addresses must be specified in such a way that they resolve correctly for **all** Gitaly
   clients.
 - Gitaly clients are:
-  - Puma or Unicorn.
+  - Puma.
   - Sidekiq.
   - GitLab Workhorse.
   - GitLab Shell.
@@ -247,7 +247,6 @@ disable enforcement. For more information, see the documentation on configuring
    # node_exporter['enable'] = false
 
    # Prevent database connections during 'gitlab-ctl reconfigure'
-   gitlab_rails['rake_cache_clear'] = false
    gitlab_rails['auto_migrate'] = false
 
    # Configure the gitlab-shell API callback URL. Without this, `git push` will
diff --git a/doc/administration/gitaly/faq.md b/doc/administration/gitaly/faq.md
new file mode 100644
index 00000000000..98a90925d32
--- /dev/null
+++ b/doc/administration/gitaly/faq.md
@@ -0,0 +1,90 @@
+---
+stage: Create
+group: Gitaly
+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
+type: reference
+---
+
+# Frequently asked questions **(FREE SELF)**
+
+The following are answers to frequently asked questions about Gitaly and Gitaly Cluster.
+
+## How does Gitaly Cluster compare to Geo?
+
+Gitaly Cluster and [Geo](../geo/index.md) both provide redundancy. However the redundancy of:
+
+- Gitaly Cluster provides fault tolerance for data storage and is invisible to the user. Users are
+  not aware when Gitaly Cluster is used.
+- Geo provides [replication](../geo/index.md) and [disaster recovery](../geo/disaster_recovery/index.md) for
+  an entire instance of GitLab. Users know when they are using Geo for
+  [replication](../geo/index.md). Geo [replicates multiple data types](../geo/replication/datatypes.md#limitations-on-replicationverification),
+  including Git data.
+
+The following table outlines the major differences between Gitaly Cluster and Geo:
+
+| Tool           | Nodes    | Locations | Latency tolerance  | Failover                                                                    | Consistency                              | Provides redundancy for |
+|:---------------|:---------|:----------|:-------------------|:----------------------------------------------------------------------------|:-----------------------------------------|:------------------------|
+| Gitaly Cluster | Multiple | Single    | Approximately 1 ms | [Automatic](praefect.md#automatic-failover-and-primary-election-strategies) | [Strong](praefect.md#strong-consistency) | Data storage in Git     |
+| Geo            | Multiple | Multiple  | Up to one minute   | [Manual](../geo/disaster_recovery/index.md)                                 | Eventual                                 | Entire GitLab instance  |
+
+For more information, see:
+
+- Geo [use cases](../geo/index.md#use-cases).
+- Geo [architecture](../geo/index.md#architecture).
+
+## Are there instructions for migrating to Gitaly Cluster?
+
+Yes! For more information, see [Migrate to Gitaly Cluster](praefect.md#migrate-to-gitaly-cluster).
+
+## What are some repository storage recommendations?
+
+The size of the required storage can vary between instances and depends on the set
+[replication factor](praefect.md#replication-factor). You might want to include implementing
+repository storage redundancy.
+
+For a replication factor:
+
+- Of `1`: NFS, Gitaly, and Gitaly Cluster have roughly the same storage requirements.
+- More than `1`: The amount of required storage is `used space * replication factor`. `used space`
+  should include any planned future growth.
+
+## What are some Praefect database storage requirements?
+
+The requirements are relatively low because the database contains only metadata of:
+
+- Where repositories are located.
+- Some queued work.
+
+It depends on the number of repositories, but a useful minimum is 5-10 GB, similar to the main
+GitLab application database.
+
+## Can the GitLab application database and the Praefect database be on the same servers?
+
+Yes, however Praefect should have it's own database server when using Omnibus GitLab PostgreSQL. If
+there is a failover, Praefect isn't aware and starts to fail as the database it's trying to use would
+either:
+
+- Be unavailable.
+- In read-only mode.
+
+A future solution may allow for Praefect and Omnibus GitLab databases on the same PostgreSQL server.
+For more information, see the relevant:
+
+- [Omnibus GitLab issue](https://gitlab.com/gitlab-org/omnibus-gitlab/-/issues/5919).
+- [Gitaly issue](https://gitlab.com/gitlab-org/gitaly/-/issues/3398).
+
+## Is PgBouncer required for the Praefect database?
+
+No, because the number of connections Praefect makes is low. You can use the same PgBouncer instance
+for both the GitLab application database and the Praefect database if you wish.
+
+## Are there any special considerations for Gitaly Cluster when PostgreSQL is upgraded?
+
+There are no special requirements. Gitaly Cluster requires PostgreSQL version 11 or later.
+
+## Praefect database tables are empty?
+
+These tables are created per the [specific configuration section](praefect.md#postgresql).
+
+If you find you have an empty Praefect database table, see the
+[relevant troubleshooting section](index.md#relation-does-not-exist-errors).
diff --git a/doc/administration/gitaly/index.md b/doc/administration/gitaly/index.md
index 3935e990590..eaf9e21780d 100644
--- a/doc/administration/gitaly/index.md
+++ b/doc/administration/gitaly/index.md
@@ -235,29 +235,6 @@ A hybrid approach can be used in these instances, where each shard is configured
 cluster. [Variable replication factor](https://gitlab.com/groups/gitlab-org/-/epics/3372) is planned
 to provide greater flexibility for extremely large GitLab instances.
 
-### Gitaly Cluster compared to Geo
-
-Gitaly Cluster and [Geo](../geo/index.md) both provide redundancy. However the redundancy of:
-
-- Gitaly Cluster provides fault tolerance for data storage and is invisible to the user. Users are
-  not aware when Gitaly Cluster is used.
-- Geo provides [replication](../geo/index.md) and [disaster recovery](../geo/disaster_recovery/index.md) for
-  an entire instance of GitLab. Users know when they are using Geo for
-  [replication](../geo/index.md). Geo [replicates multiple data types](../geo/replication/datatypes.md#limitations-on-replicationverification),
-  including Git data.
-
-The following table outlines the major differences between Gitaly Cluster and Geo:
-
-| Tool           | Nodes    | Locations | Latency tolerance  | Failover                                                                    | Consistency                              | Provides redundancy for |
-|:---------------|:---------|:----------|:-------------------|:----------------------------------------------------------------------------|:-----------------------------------------|:------------------------|
-| Gitaly Cluster | Multiple | Single    | Approximately 1 ms | [Automatic](praefect.md#automatic-failover-and-primary-election-strategies) | [Strong](praefect.md#strong-consistency) | Data storage in Git     |
-| Geo            | Multiple | Multiple  | Up to one minute   | [Manual](../geo/disaster_recovery/index.md)                                 | Eventual                                 | Entire GitLab instance  |
-
-For more information, see:
-
-- Geo [use cases](../geo/index.md#use-cases).
-- Geo [architecture](../geo/index.md#architecture).
-
 ### Architecture
 
 Praefect is a router and transaction manager for Gitaly, and a required
@@ -346,7 +323,6 @@ When GitLab calls a function that has a "Rugged patch", it performs two checks:
   the GitLab use of "Rugged patch" code.
 - If the feature flag is not set, GitLab tries accessing the file system underneath the
   Gitaly server directly. If it can, it uses the "Rugged patch":
-  - If using Unicorn.
   - If using Puma and [thread count](../../install/requirements.md#puma-threads) is set
     to `1`.
 
@@ -404,25 +380,36 @@ GitLab recommends:
 
 We welcome your feedback on this process: raise a support ticket, or [comment on the epic](https://gitlab.com/groups/gitlab-org/-/epics/4916).
 
-## Troubleshooting Gitaly
+## Troubleshooting
+
+Refer to the information below when troubleshooting Gitaly and Gitaly Cluster.
+
+Before troubleshooting, see the Gitaly and Gitaly Cluster
+[frequently asked questions](faq.md).
+
+### Troubleshoot Gitaly
+
+The following sections provide possible solutions to Gitaly errors.
 
-Check [Gitaly timeouts](../../user/admin_area/settings/gitaly_timeouts.md) when troubleshooting
-Gitaly.
+See also [Gitaly timeout](../../user/admin_area/settings/gitaly_timeouts.md) settings.
 
-### Check versions when using standalone Gitaly servers
+#### Check versions when using standalone Gitaly servers
 
 When using standalone Gitaly servers, you must make sure they are the same version
-as GitLab to ensure full compatibility. Check **Admin Area > Overview > Gitaly Servers** on
-your GitLab instance and confirm all Gitaly servers indicate that they are up to date.
+as GitLab to ensure full compatibility:
 
-### `gitaly-debug`
+1. On the top bar, select **Menu >** **{admin}** **Admin** on your GitLab instance.
+1. On the left sidebar, select **Overview > Gitaly Servers**.
+1. Confirm all Gitaly servers indicate that they are up to date.
+
+#### Use `gitaly-debug`
 
 The `gitaly-debug` command provides "production debugging" tools for Gitaly and Git
 performance. It is intended to help production engineers and support
 engineers investigate Gitaly performance problems.
 
 If you're using GitLab 11.6 or newer, this tool should be installed on
-your GitLab / Gitaly server already at `/opt/gitlab/embedded/bin/gitaly-debug`.
+your GitLab or Gitaly server already at `/opt/gitlab/embedded/bin/gitaly-debug`.
 If you're investigating an older GitLab version you can compile this
 tool offline and copy the executable to your server:
 
@@ -438,19 +425,19 @@ To see the help page of `gitaly-debug` for a list of supported sub-commands, run
 gitaly-debug -h
 ```
 
-### Commits, pushes, and clones return a 401
+#### Commits, pushes, and clones return a 401
 
 ```plaintext
 remote: GitLab: 401 Unauthorized
 ```
 
-You need to sync your `gitlab-secrets.json` file with your Gitaly clients (GitLab
-app nodes).
+You need to sync your `gitlab-secrets.json` file with your GitLab
+application nodes.
 
-### Client side gRPC logs
+#### Client side gRPC logs
 
 Gitaly uses the [gRPC](https://grpc.io/) RPC framework. The Ruby gRPC
-client has its own log file which may contain debugging information when
+client has its own log file which may contain useful information when
 you are seeing Gitaly errors. You can control the log level of the
 gRPC client with the `GRPC_LOG_LEVEL` environment variable. The
 default level is `WARN`.
@@ -461,7 +448,7 @@ You can run a gRPC trace with:
 sudo GRPC_TRACE=all GRPC_VERBOSITY=DEBUG gitlab-rake gitlab:gitaly:check
 ```
 
-### Server side gRPC logs
+#### Server side gRPC logs
 
 gRPC tracing can also be enabled in Gitaly itself with the `GODEBUG=http2debug`
 environment variable. To set this in an Omnibus GitLab install:
@@ -476,7 +463,7 @@ environment variable. To set this in an Omnibus GitLab install:
 
 1. [Reconfigure](../restart_gitlab.md#omnibus-gitlab-reconfigure) GitLab.
 
-### Correlating Git processes with RPCs
+#### Correlating Git processes with RPCs
 
 Sometimes you need to find out which Gitaly RPC created a particular Git process.
 
@@ -494,7 +481,7 @@ sudo cat /proc/$PID/environ | tr '\0' '\n' | grep ^CORRELATION_ID=
 This method isn't reliable for `git cat-file` processes, because Gitaly
 internally pools and re-uses those across RPCs.
 
-### Observing `gitaly-ruby` traffic
+#### Observing `gitaly-ruby` traffic
 
 [`gitaly-ruby`](configure_gitaly.md#gitaly-ruby) is an internal implementation detail of Gitaly,
 so, there's not that much visibility into what goes on inside
@@ -502,12 +489,13 @@ so, there's not that much visibility into what goes on inside
 
 If you have Prometheus set up to scrape your Gitaly process, you can see
 request rates and error codes for individual RPCs in `gitaly-ruby` by
-querying `grpc_client_handled_total`. Strictly speaking, this metric does
-not differentiate between `gitaly-ruby` and other RPCs. However from GitLab 11.9,
-all gRPC calls made by Gitaly itself are internal calls from the main Gitaly process to one of its
-`gitaly-ruby` sidecars.
+querying `grpc_client_handled_total`.
+
+- In theory, this metric does not differentiate between `gitaly-ruby` and other RPCs.
+- In practice from GitLab 11.9, all gRPC calls made by Gitaly itself are internal calls from the
+  main Gitaly process to one of its `gitaly-ruby` sidecars.
 
-Assuming your `grpc_client_handled_total` counter observes only Gitaly,
+Assuming your `grpc_client_handled_total` counter only observes Gitaly,
 the following query shows you RPCs are (most likely) internally
 implemented as calls to `gitaly-ruby`:
 
@@ -515,7 +503,7 @@ implemented as calls to `gitaly-ruby`:
 sum(rate(grpc_client_handled_total[5m])) by (grpc_method) > 0
 ```
 
-### Repository changes fail with a `401 Unauthorized` error
+#### Repository changes fail with a `401 Unauthorized` error
 
 If you run Gitaly on its own server and notice these conditions:
 
@@ -541,7 +529,7 @@ Confirm the following are all true:
 - When any user adds or modifies a file from the repository using the GitLab
   UI, it immediately fails with a red `401 Unauthorized` banner.
 - Creating a new project and [initializing it with a README](../../user/project/working_with_projects.md#blank-projects)
-  successfully creates the project, but doesn't create the README.
+  successfully creates the project but doesn't create the README.
 - When [tailing the logs](https://docs.gitlab.com/omnibus/settings/logs.html#tail-logs-in-a-console-on-the-server)
   on a Gitaly client and reproducing the error, you get `401` errors
   when reaching the [`/api/v4/internal/allowed`](../../development/internal_api.md) endpoint:
@@ -610,7 +598,7 @@ on the Gitaly server matches the one on Gitaly client. If it doesn't match,
 update the secrets file on the Gitaly server to match the Gitaly client, then
 [reconfigure](../restart_gitlab.md#omnibus-gitlab-reconfigure).
 
-### Command line tools cannot connect to Gitaly
+#### Command line tools cannot connect to Gitaly
 
 gRPC cannot reach your Gitaly server if:
 
@@ -623,22 +611,24 @@ Verify you can reach Gitaly by using TCP:
 sudo gitlab-rake gitlab:tcp_check[GITALY_SERVER_IP,GITALY_LISTEN_PORT]
 ```
 
-If the TCP connection fails, check your network settings and your firewall rules.
-If the TCP connection succeeds, your networking and firewall rules are correct.
+If the TCP connection:
+
+- Fails, check your network settings and your firewall rules.
+- Succeeds, your networking and firewall rules are correct.
 
-If you use proxy servers in your command line environment, such as Bash, these
-can interfere with your gRPC traffic.
+If you use proxy servers in your command line environment such as Bash, these can interfere with
+your gRPC traffic.
 
-If you use Bash or a compatible command line environment, run the following commands
-to determine whether you have proxy servers configured:
+If you use Bash or a compatible command line environment, run the following commands to determine
+whether you have proxy servers configured:
 
 ```shell
 echo $http_proxy
 echo $https_proxy
 ```
 
-If either of these variables have a value, your Gitaly CLI connections may be
-getting routed through a proxy which cannot connect to Gitaly.
+If either of these variables have a value, your Gitaly CLI connections may be getting routed through
+a proxy which cannot connect to Gitaly.
 
 To remove the proxy setting, run the following commands (depending on which variables had values):
 
@@ -647,7 +637,7 @@ unset http_proxy
 unset https_proxy
 ```
 
-### Permission denied errors appearing in Gitaly or Praefect logs when accessing repositories
+#### Permission denied errors appearing in Gitaly or Praefect logs when accessing repositories
 
 You might see the following in Gitaly and Praefect logs:
 
@@ -668,9 +658,87 @@ This is a GRPC call
 [error response code](https://grpc.github.io/grpc/core/md_doc_statuscodes.html).
 
 If this error occurs, even though
-[the Gitaly auth tokens are correctly setup](../gitaly/praefect.md#debugging-praefect),
+[the Gitaly auth tokens are set up correctly](#praefect-errors-in-logs),
 it's likely that the Gitaly servers are experiencing
 [clock drift](https://en.wikipedia.org/wiki/Clock_drift).
 
 Ensure the Gitaly clients and servers are synchronized, and use an NTP time
 server to keep them synchronized.
+
+#### Gitaly not listening on new address after reconfiguring
+
+When updating the `gitaly['listen_addr']` or `gitaly['prometheus_listen_addr']` values, Gitaly may
+continue to listen on the old address after a `sudo gitlab-ctl reconfigure`.
+
+When this occurs, run `sudo gitlab-ctl restart` to resolve the issue. This should no longer be
+necessary because [this issue](https://gitlab.com/gitlab-org/gitaly/-/issues/2521) is resolved.
+
+#### Permission denied errors appearing in Gitaly logs when accessing repositories from a standalone Gitaly node
+
+If this error occurs even though file permissions are correct, it's likely that the Gitaly node is
+experiencing [clock drift](https://en.wikipedia.org/wiki/Clock_drift).
+
+Please ensure that the GitLab and Gitaly nodes are synchronized and use an NTP time
+server to keep them synchronized if possible.
+
+### Troubleshoot Praefect (Gitaly Cluster)
+
+The following sections provide possible solutions to Gitaly Cluster errors.
+
+#### Praefect errors in logs
+
+If you receive an error, check `/var/log/gitlab/gitlab-rails/production.log`.
+
+Here are common errors and potential causes:
+
+- 500 response code
+  - **ActionView::Template::Error (7:permission denied)**
+    - `praefect['auth_token']` and `gitlab_rails['gitaly_token']` do not match on the GitLab server.
+  - **Unable to save project. Error: 7:permission denied**
+    - Secret token in `praefect['storage_nodes']` on GitLab server does not match the
+      value in `gitaly['auth_token']` on one or more Gitaly servers.
+- 503 response code
+  - **GRPC::Unavailable (14:failed to connect to all addresses)**
+    - GitLab was unable to reach Praefect.
+  - **GRPC::Unavailable (14:all SubCons are in TransientFailure...)**
+    - Praefect cannot reach one or more of its child Gitaly nodes. Try running
+      the Praefect connection checker to diagnose.
+
+#### Determine primary Gitaly node
+
+To determine the current primary Gitaly node for a specific Praefect node:
+
+- Use the `Shard Primary Election` [Grafana chart](praefect.md#grafana) on the
+  [`Gitlab Omnibus - Praefect` dashboard](https://gitlab.com/gitlab-org/grafana-dashboards/-/blob/master/omnibus/praefect.json).
+  This is recommended.
+- If you do not have Grafana set up, use the following command on each host of each
+  Praefect node:
+
+  ```shell
+  curl localhost:9652/metrics | grep gitaly_praefect_primaries`
+  ```
+
+#### Relation does not exist errors
+
+By default Praefect database tables are created automatically by `gitlab-ctl reconfigure` task.
+However, if the `gitlab-ctl reconfigure` command isn't executed or there are errors during the
+execution, the Praefect database tables are not created on initial reconfigure and can throw
+errors that relations do not exist.
+
+For example:
+
+- `ERROR:  relation "node_status" does not exist at character 13`
+- `ERROR:  relation "replication_queue_lock" does not exist at character 40`
+- This error:
+
+  ```json
+  {"level":"error","msg":"Error updating node: pq: relation \"node_status\" does not exist","pid":210882,"praefectName":"gitlab1x4m:0.0.0.0:2305","time":"2021-04-01T19:26:19.473Z","virtual_storage":"praefect-cluster-1"}
+  ```
+
+To solve this, the database schema migration can be done using `sql-migrate` sub-command of
+the `praefect` command:
+
+```shell
+$ sudo /opt/gitlab/embedded/bin/praefect -config /var/opt/gitlab/praefect/config.toml sql-migrate
+praefect sql-migrate: OK (applied 21 migrations)
+```
diff --git a/doc/administration/gitaly/praefect.md b/doc/administration/gitaly/praefect.md
index a1733d9d6ac..21e5360e27b 100644
--- a/doc/administration/gitaly/praefect.md
+++ b/doc/administration/gitaly/praefect.md
@@ -9,13 +9,21 @@ type: reference
 
 Configure Gitaly Cluster using either:
 
-- The Gitaly Cluster configuration instructions available as part of
-  [reference architectures](../reference_architectures/index.md) for installations for more than
-  2000 users.
-- The advanced configuration instructions that follow on this page.
+- Gitaly Cluster configuration instructions available as part of
+  [reference architectures](../reference_architectures/index.md) for installations of up to:
+  - [3000 users](../reference_architectures/3k_users.md#configure-gitaly-cluster).
+  - [5000 users](../reference_architectures/5k_users.md#configure-gitaly-cluster).
+  - [10,000 users](../reference_architectures/10k_users.md#configure-gitaly-cluster).
+  - [25,000 users](../reference_architectures/25k_users.md#configure-gitaly-cluster).
+  - [50,000 users](../reference_architectures/50k_users.md#configure-gitaly-cluster).
+- The custom configuration instructions that follow on this page.
 
 Smaller GitLab installations may need only [Gitaly itself](index.md).
 
+NOTE:
+Upgrade instructions for Omnibus GitLab installations
+[are available](https://docs.gitlab.com/omnibus/update/#gitaly-cluster).
+
 ## Requirements for configuring a Gitaly Cluster
 
 The minimum recommended configuration for a Gitaly Cluster requires:
@@ -161,6 +169,9 @@ node, using `psql` which is installed by Omnibus GitLab.
 
 The database used by Praefect is now configured.
 
+If you see Praefect database errors after configuring PostgreSQL, see
+[troubleshooting steps](index.md#relation-does-not-exist-errors).
+
 #### PgBouncer
 
 To reduce PostgreSQL resource consumption, we recommend setting up and configuring
@@ -223,8 +234,10 @@ PostgreSQL instances. Otherwise you should change the configuration parameter
 
 > [Introduced](https://gitlab.com/gitlab-org/gitaly/-/issues/2634) in GitLab 13.4, Praefect nodes can no longer be designated as `primary`.
 
-NOTE:
-If there are multiple Praefect nodes, complete these steps for **each** node.
+If there are multiple Praefect nodes:
+
+- Complete the following steps for **each** node.
+- Designate one node as the "deploy node", and configure it first.
 
 To complete this section you need a [configured PostgreSQL server](#postgresql), including:
 
@@ -259,8 +272,8 @@ application server, or a Gitaly node.
    praefect['enable'] = true
 
    # Prevent database connections during 'gitlab-ctl reconfigure'
-   gitlab_rails['rake_cache_clear'] = false
    gitlab_rails['auto_migrate'] = false
+   praefect['auto_migrate'] = false
    ```
 
 1. Configure **Praefect** to listen on network interfaces by editing
@@ -381,6 +394,30 @@ application server, or a Gitaly node.
    gitlab-ctl reconfigure
    ```
 
+1. For:
+
+   - The "deploy node":
+     1. Enable Praefect auto-migration again by setting `praefect['auto_migrate'] = true` in
+        `/etc/gitlab/gitlab.rb`.
+     1. To ensure database migrations are only run during reconfigure and not automatically on
+        upgrade, run:
+
+        ```shell
+        sudo touch /etc/gitlab/skip-auto-reconfigure
+        ```
+
+   - The other nodes, you can leave the settings as they are. Though
+     `/etc/gitlab/skip-auto-reconfigure` isn't required, you may want to set it to prevent GitLab
+     running reconfigure automatically when running commands such as `apt-get update`. This way any
+     additional configuration changes can be done and then reconfigure can be run manually.
+
+1. Save the changes to `/etc/gitlab/gitlab.rb` and [reconfigure
+   Praefect](../restart_gitlab.md#omnibus-gitlab-reconfigure):
+
+   ```shell
+   gitlab-ctl reconfigure
+   ```
+
 1. To ensure that Praefect [has updated its Prometheus listen
    address](https://gitlab.com/gitlab-org/gitaly/-/issues/2734), [restart
    Praefect](../restart_gitlab.md#omnibus-gitlab-restart):
@@ -599,7 +636,6 @@ documentation](configure_gitaly.md#configure-gitaly-servers).
    prometheus['enable'] = true
 
    # Prevent database connections during 'gitlab-ctl reconfigure'
-   gitlab_rails['rake_cache_clear'] = false
    gitlab_rails['auto_migrate'] = false
    ```
 
@@ -696,7 +732,7 @@ documentation](configure_gitaly.md#configure-gitaly-servers).
 
 **The steps above must be completed for each Gitaly node!**
 
-After all Gitaly nodes are configured, you can run the Praefect connection
+After all Gitaly nodes are configured, run the Praefect connection
 checker to verify Praefect can connect to all Gitaly servers in the Praefect
 configuration.
 
@@ -865,9 +901,13 @@ Particular attention should be shown to:
    gitlab-rake gitlab:gitaly:check
    ```
 
-1. Check in **Admin Area > Settings > Repository > Repository storage** that the Praefect storage
-   is configured to store new repositories. Following this guide, the `default` storage should have
-   weight 100 to store all new repositories.
+1. Check that the Praefect storage is configured to store new repositories:
+
+   1. On the top bar, select **Menu >** **{admin}** **Admin**.
+   1. On the left sidebar, select **Settings > Repository**.
+   1. Expand the **Repository storage** section.
+
+   Following this guide, the `default` storage should have weight 100 to store all new repositories.
 
 1. Verify everything is working by creating a new project. Check the
    "Initialize repository with a README" box so that there is content in the
@@ -878,7 +918,7 @@ Particular attention should be shown to:
 
 When adding Gitaly Cluster to an existing Gitaly instance, the existing Gitaly storage
 must use a TCP address. If `gitaly_address` is not specified, then a Unix socket is used,
-which will prevent the communication with the cluster.
+which prevents the communication with the cluster.
 
 For example:
 
@@ -1160,15 +1200,36 @@ To migrate existing clusters:
    a Praefect node to reattempt it. The migration only runs with `sql` election strategy configured.
 
 1. Running two different election strategies side by side can cause a split brain, where different
-   Praefect nodes consider repositories to have different primaries. To avoid this, shut down
-   all Praefect nodes before changing the election strategy.
+   Praefect nodes consider repositories to have different primaries. This can be avoided either:
+
+   - If a short downtime is acceptable:
 
-   Do this by running `gitlab-ctl stop praefect` on the Praefect nodes.
+      1. Shut down all Praefect nodes before changing the election strategy. Do this by running `gitlab-ctl stop praefect` on the Praefect nodes.
 
-1. On the Praefect nodes, configure the election strategy in `/etc/gitlab/gitlab.rb` with
-   `praefect['failover_election_strategy'] = 'per_repository'`.
+      1. On the Praefect nodes, configure the election strategy in `/etc/gitlab/gitlab.rb` with `praefect['failover_election_strategy'] = 'per_repository'`.
 
-1. Finally, run `gitlab-ctl reconfigure` to reconfigure and restart the Praefect nodes.
+      1. Run `gitlab-ctl reconfigure && gitlab-ctl start` to reconfigure and start the Praefects.
+
+   - If downtime is unacceptable:
+
+      1. Determine which Gitaly node is [the current primary](index.md#determine-primary-gitaly-node).
+
+      1. Comment out the secondary Gitaly nodes from the virtual storage's configuration in `/etc/gitlab/gitlab.rb`
+      on all Praefect nodes. This ensures there's only one Gitaly node configured, causing both of the election
+      strategies to elect the same Gitaly node as the primary.
+
+      1. Run `gitlab-ctl reconfigure` on all Praefect nodes. Wait until all Praefect processes have restarted and
+      the old processes have exited. This can take up to one minute.
+
+      1. On all Praefect nodes, configure the election strategy in `/etc/gitlab/gitlab.rb` with
+      `praefect['failover_election_strategy'] = 'per_repository'`.
+
+      1. Run `gitlab-ctl reconfigure` on all Praefect nodes. Wait until all of the Praefect processes have restarted and
+      the old processes have exited. This can take up to one minute.
+
+      1. Uncomment the secondary Gitaly node configuration commented out in the earlier step on all Praefect nodes.
+
+      1. Run `gitlab-ctl reconfigure` on all Praefect nodes to reconfigure and restart the Praefect processes.
 
 ### Deprecated election strategies
 
@@ -1428,15 +1489,8 @@ or to move from single Gitaly nodes, the basic process involves:
 1. Create and configure Gitaly Cluster.
 1. [Move the repositories](#move-repositories).
 
-The size of the required storage can vary between instances and depends on the set
-[replication factor](#replication-factor). The migration to Gitaly Cluster might include
-implementing repository storage redundancy.
-
-For a replication factor:
-
-- Of `1`: NFS, Gitaly, and Gitaly Cluster have roughly the same storage requirements.
-- More than `1`: The amount of required storage is `used space * replication factor`. `used space`
-  should include any planned future growth.
+When creating the storage, see some
+[repository storage recommendations](faq.md#what-are-some-repository-storage-recommendations).
 
 ### Move Repositories
 
@@ -1467,8 +1521,10 @@ After creating and configuring Gitaly Cluster:
 1. [Schedule repository storage moves for all projects on a storage shard](../../api/project_repository_storage_moves.md#schedule-repository-storage-moves-for-all-projects-on-a-storage-shard) using the API. For example:
 
    ```shell
-   curl --request POST --header "Private-Token: <your_access_token>" --header "Content-Type: application/json" \
-   --data '{"source_storage_name":"<original_storage_name>","destination_storage_name":"<cluster_storage_name>"}' "https://gitlab.example.com/api/v4/project_repository_storage_moves"
+   curl --request POST --header "Private-Token: <your_access_token>" \
+        --header "Content-Type: application/json" \
+        --data '{"source_storage_name":"<original_storage_name>","destination_storage_name":"<cluster_storage_name>"}' \
+        "https://gitlab.example.com/api/v4/project_repository_storage_moves"
    ```
 
 1. [Query the most recent repository moves](../../api/project_repository_storage_moves.md#retrieve-all-project-repository-storage-moves)
@@ -1500,8 +1556,10 @@ After creating and configuring Gitaly Cluster:
 1. [Schedule repository storage moves for all snippets on a storage shard](../../api/snippet_repository_storage_moves.md#schedule-repository-storage-moves-for-all-snippets-on-a-storage-shard) using the API. For example:
 
    ```shell
-   curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" --header "Content-Type: application/json" \
-   --data '{"source_storage_name":"<original_storage_name>","destination_storage_name":"<cluster_storage_name>"}' "https://gitlab.example.com/api/v4/snippet_repository_storage_moves"
+   curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" \
+        --header "Content-Type: application/json" \
+        --data '{"source_storage_name":"<original_storage_name>","destination_storage_name":"<cluster_storage_name>"}' \
+        "https://gitlab.example.com/api/v4/snippet_repository_storage_moves"
    ```
 
 1. [Query the most recent repository moves](../../api/snippet_repository_storage_moves.md#retrieve-all-snippet-repository-storage-moves)
@@ -1525,8 +1583,10 @@ After creating and configuring Gitaly Cluster:
 1. [Schedule repository storage moves for all groups on a storage shard](../../api/group_repository_storage_moves.md#schedule-repository-storage-moves-for-all-groups-on-a-storage-shard) using the API.
 
     ```shell
-    curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" --header "Content-Type: application/json" \
-    --data '{"source_storage_name":"<original_storage_name>","destination_storage_name":"<cluster_storage_name>"}' "https://gitlab.example.com/api/v4/group_repository_storage_moves"
+    curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" \
+         --header "Content-Type: application/json" \
+         --data '{"source_storage_name":"<original_storage_name>","destination_storage_name":"<cluster_storage_name>"}' \
+         "https://gitlab.example.com/api/v4/group_repository_storage_moves"
     ```
 
 1. [Query the most recent repository moves](../../api/group_repository_storage_moves.md#retrieve-all-group-repository-storage-moves)
@@ -1544,35 +1604,3 @@ After creating and configuring Gitaly Cluster:
    ```
 
 1. Repeat for each storage as required.
-
-## Debugging Praefect
-
-If you receive an error, check `/var/log/gitlab/gitlab-rails/production.log`.
-
-Here are common errors and potential causes:
-
-- 500 response code
-  - **ActionView::Template::Error (7:permission denied)**
-    - `praefect['auth_token']` and `gitlab_rails['gitaly_token']` do not match on the GitLab server.
-  - **Unable to save project. Error: 7:permission denied**
-    - Secret token in `praefect['storage_nodes']` on GitLab server does not match the
-      value in `gitaly['auth_token']` on one or more Gitaly servers.
-- 503 response code
-  - **GRPC::Unavailable (14:failed to connect to all addresses)**
-    - GitLab was unable to reach Praefect.
-  - **GRPC::Unavailable (14:all SubCons are in TransientFailure...)**
-    - Praefect cannot reach one or more of its child Gitaly nodes. Try running
-      the Praefect connection checker to diagnose.
-
-### Determine primary Gitaly node
-
-To determine the current primary Gitaly node for a specific Praefect node:
-
-- Use the `Shard Primary Election` [Grafana chart](#grafana) on the [`Gitlab Omnibus - Praefect` dashboard](https://gitlab.com/gitlab-org/grafana-dashboards/-/blob/master/omnibus/praefect.json).
-  This is recommended.
-- If you do not have Grafana set up, use the following command on each host of each
-  Praefect node:
-
-  ```shell
-  curl localhost:9652/metrics | grep gitaly_praefect_primaries`
-  ```