Comment on datashield volume

ccp/modules/datashield-compose.yml

@@ -58,6 +58,8 @@ services:
       POSTGRES_PASSWORD: "${OPAL_DB_PASSWORD}" # Set in datashield-setup.sh
       POSTGRES_USER: "opal"
       POSTGRES_DB: "opal"
+  # Please evaluate if this volume makes sense. An import can take several hours. If the bridgehead is restarted,
+  # the data should be reimported again.
   #    volumes:
   #      - "bridgehead-opal-db:/var/lib/postgresql/data"