Add rake task to clean orphan artifact filestc-rake-orphan-artifacts

This adds the rake task rake
gitlab:cleanup:orphan_job_artifact_files. This rake task cleans all
orphan job artifact files it can find on disk.

 It performs a search on the complete folder of all artifacts on
disk. Then it filters out all the job artifact ID for which it could
not find a record with matching ID in the database. For these, the
file is deleted from disk.

1 files changed, 9 insertions, 0 deletions

diff --git a/doc/administration/geo/replication/troubleshooting.md b/doc/administration/geo/replication/troubleshooting.md
index 5394e6dd763..5bd6cc81362 100644
--- a/doc/administration/geo/replication/troubleshooting.md
+++ b/doc/administration/geo/replication/troubleshooting.md
@@ -504,6 +504,15 @@ To resolve this, run the following command:
 sudo gitlab-rake geo:db:refresh_foreign_tables
 ```
 
+## Expired artifacts
+
+If you notice for some reason there are more artifacts on the Geo
+secondary node than on the Geo primary node, you can use the rake task
+to [cleanup orphan artifact files](../../../raketasks/cleanup.md#remove-orphan-artifact-files).
+
+On a Geo **secondary** node, this command will also clean up all Geo
+registry record related to the orphan files on disk.
+
 ## Fixing common errors
 
 This section documents common errors reported in the Admin UI and how to fix them.