diff --git a/tests/functional/centos/7/cluster/ceph-override.json b/tests/functional/centos/7/cluster/ceph-override.json
index d0df1fa78..cce7e62e8 100644
--- a/tests/functional/centos/7/cluster/ceph-override.json
+++ b/tests/functional/centos/7/cluster/ceph-override.json
@@ -1,7 +1,8 @@
 {
 	"ceph_conf_overrides": {
 		"global": {
-			"osd_pool_default_pg_num": 12
+			"osd_pool_default_pg_num": 12,
+			"osd_pool_default_size": 1
 		}
 	},
 	"cephfs_pools": [