The relational datastore backup failed. The database backup files were not created

Error Message

When attempting to connect a new standby data store to an ArcGIS Enterprise site, the process fails, and returns the following error:

Error:   
The relational datastore backup failed. The database backup files were not created.

The standby data store log file displays the following error:

Error:   
pg_basebackup: could not write file "<standby_data_store_installation_directory>\arcgis\arcgisdatastore\pgdata\base\<folder_name>\<file_name>": No space left on device

Cause

The ArcGIS Data Store installation directory does not have enough drive space.

Solution or Workaround

Remove old backup files from the ArcGIS Data Store directory, or allocate more space to the ArcGIS Data Store directory drive. The default directory for ArcGIS Data Store is:

C:\arcgis\arcgisdatastore

This process must be performed by the organization's IT.