A huge number of pull-mirror jobs on GitLab.com have not succeeded in a very long time, but continue to be processed multiple times a day. On each attempt, we will attempt three retries, and eventually fail the job to the deadletter queue. `repository_update_mirror` jobs are in fact the number one source of deadletter queue entries in Sidekiq on GitLab.com. One possible solution would be to add an instance-wide option to disable pull repository mirroring after n successive mirror update failures. (I am also open to other options but am starting with this proposal :smile:) Related to https://gitlab.com/gitlab-org/gitlab-ce/issues/44046