Database Backup Volume
Server migration or upgrade with mgradm migration or mgradm upgrade can create a volume with the database backup.
When the PostgreSQL database version is increased, the old database must be stored in a separate location before running the upgrade.
For this purpose mgradm dynamically creates the volume var-pgsql-backup.
When the migration or upgrade is done and the user has validated that the new system is working as expected, this volume can be removed safely.