diff --git a/src/storage/storage_backend_fs.c b/src/storage/storage_backend_fs.c
index d575b75449..c2d0d7bd1f 100644
--- a/src/storage/storage_backend_fs.c
+++ b/src/storage/storage_backend_fs.c
@@ -705,6 +705,7 @@ static virXMLNamespace virStoragePoolFSXMLNamespace = {
     .parse = virStoragePoolDefFSNamespaceParse,
     .free = virStoragePoolDefFSNamespaceFree,
     .format = virStoragePoolDefFSNamespaceFormatXML,
+    .prefix = "fs",
     .href = virStoragePoolDefFSNamespaceHref,
 };
 #endif /* WITH_STORAGE_FS */
diff --git a/src/storage/storage_backend_rbd.c b/src/storage/storage_backend_rbd.c
index e490c690f5..f86df9a2fa 100644
--- a/src/storage/storage_backend_rbd.c
+++ b/src/storage/storage_backend_rbd.c
@@ -1546,6 +1546,7 @@ static virXMLNamespace virStoragePoolRBDXMLNamespace = {
     .parse = virStoragePoolDefRBDNamespaceParse,
     .free = virStoragePoolDefRBDNamespaceFree,
     .format = virStoragePoolDefRBDNamespaceFormatXML,
+    .prefix = "rbd",
     .href = virStoragePoolDefRBDNamespaceHref,
 };