Docs feedback: Clarify safe way to move to new server via backup and restore

https://docs.gitlab.com/ee/raketasks/backup_restore.html states

The best way to migrate your repositories from one server to another is through backup restore.

But gives very few details on this. How do I safely without data loss move GitLab from old server to new?

• What do I do about Redis and Sidekiq data which does not appear to be in backup?
  • e.g. how do I allow sidekiq jobs to finish safely/drain sidekiq? Or do I somehow move queued jobs to new server?
  • Do I care about Redis? I thought no but then https://docs.gitlab.com/ee/administration/reference_architectures/50k_users.html has something about Redis Persistent which makes me think perhaps Redis is being used as more than just cache?
• How do I shutdown GitLab so no new data is created but leave enough services running to take a backup?
  • Just sudo gitlab-ctl stop puma sidekiq then take the backup?