diff --git a/src/modules/dataman/dataman.c b/src/modules/dataman/dataman.c
index 817b65dce3..aaa10b3318 100644
--- a/src/modules/dataman/dataman.c
+++ b/src/modules/dataman/dataman.c
@@ -860,8 +860,8 @@ start(void)
 
 	px4_sem_init(&g_init_sema, 1, 0);
 
-	/* start the worker thread */
-	if ((task = px4_task_spawn_cmd("dataman", SCHED_DEFAULT, SCHED_PRIORITY_DEFAULT, 1500, task_main, NULL)) <= 0) {
+	/* start the worker thread with low priority for disk IO */
+	if ((task = px4_task_spawn_cmd("dataman", SCHED_DEFAULT, SCHED_PRIORITY_DEFAULT - 10, 1500, task_main, NULL)) <= 0) {
 		warn("task start failed");
 		return -1;
 	}