diff --git a/data/common/common.yaml b/data/common/common.yaml
--- a/data/common/common.yaml
+++ b/data/common/common.yaml
@@ -1878,9 +1878,10 @@
 swh::deploy::deposit::config:
   max_upload_size: 209715200
   scheduler: "%{alias('swh::remote_service::scheduler::config::writable')}"
-  storage: "%{alias('swh::remote_service::storage::config')}"
-  storage_metadata: "%{alias('swh::remote_service::storage::config')}"
-  storage: "%{alias('swh::remote_service::storage::config')}"
+  # The backend server writes raw_extrinsic_metadata objects
+  storage_metadata: "%{alias('swh::remote_service::storage::config::writable')}"
+  # It only reads some information from this storage, but use the same config for consistency.
+  storage: "%{alias('swh::remote_service::storage::config::writable')}"
   private:
     secret_key: "%{hiera('swh::deploy::deposit::runtime_secret_key')}"
     db:
diff --git a/data/hostname/moma.softwareheritage.org.yaml b/data/hostname/moma.softwareheritage.org.yaml
--- a/data/hostname/moma.softwareheritage.org.yaml
+++ b/data/hostname/moma.softwareheritage.org.yaml
@@ -27,6 +27,8 @@
 
 swh::deploy::storage::db::host: somerset.internal.softwareheritage.org
 swh::deploy::storage::backend::workers: 16
+swh::deploy::storage::db::user: guest
+swh::deploy::storage::db::password: guest
 
 hitch::frontend: "[*]:443"
 hitch::proxy_support: true