如果是用docker-compose 运行的gitlab，gitlab备份配置参数，也是可以修改的，可以通过environment配置一下

environment:
      GITLAB_OMNIBUS_CONFIG: |
        # Add any other gitlab.rb configuration here, each on its own line
        external_url 'http://127.0.0.1:8180'
        gitlab_rails['backup_keep_time'] = 604800