Synced repository will behave as a "git clone --mirror".

Will git fetch with "--prune"

app/models/repository.rb

@@ -181,6 +181,13 @@ class Repository
     raw_repository.remote_update(name, url: url)
   end
 
+  def set_remote_as_mirror(name)
+    # This is used by Gitlab Geo to define repository as equivalent as "git clone --mirror"
+    raw_repository.rugged.config["remote.#{name}.fetch"]='refs/*:refs/*'
+    raw_repository.rugged.config["remote.#{name}.mirror"]=true
+    raw_repository.rugged.config["remote.#{name}.prune"]=true
+  end
+
   def fetch_remote(remote)
     gitlab_shell.fetch_remote(path_with_namespace, remote)
   end
@@ -742,6 +749,12 @@ class Repository
     fetch_remote(Repository::MIRROR_REMOTE)
   end
 
+  def fetch_geo_mirror(url)
+    add_remote(Repository::MIRROR_REMOTE, url)
+    set_remote_as_mirror(Repository::MIRROR_REMOTE)
+    fetch_remote(Repository::MIRROR_REMOTE)
+  end
+
   def upstream_branches
     rugged.references.each("refs/remotes/#{Repository::MIRROR_REMOTE}/*").map do |ref|
       name = ref.name.sub(/\Arefs\/remotes\/#{Repository::MIRROR_REMOTE}\//, "")

app/workers/geo_repository_update_worker.rb

@@ -10,13 +10,11 @@ class GeoRepositoryUpdateWorker
     @project = Project.find(project_id)
 
     fetch_repository(@project.repository, @project.url_to_repo)
-    # @current_user = @project.mirror_user || @project.creator
-    # Projects::UpdateMirrorService.new(@project, @current_user).execute
   end
 
   private
 
   def fetch_repository(repository, remote_url)
-    repository.fetch_upstream(remote_url)
+    repository.fetch_geo_mirror(remote_url)
   end
 end