Hi Daria,
metadata are stored in PostgreSQL database, which can be a part of
GD.CN deployment or you can configure your own, e.g. AWS RDS.
The one in
GD.CN is running in HA setup, outside
GD.CN you can utilize e.g. Aurora to achieve HA.
GD.CN does not contain any jobs taking care of backups of this database. It's up to you to configure it.