Import previous gitlab hashed bare repo to new gitlab

I have a gitlab instance on a machine, unfortunatelly this machine cannot connected again, so I lost gitlab data, but I still have those hashed bare repo direcotry, backup in another disk directory named backup_dir, how to import these project into a new gitlab instance just by spcifiy git_data_dirs to backup_dir in gitlab.rb, not copy all those projects, it’s huge…