+ /**
+ * is_rotational
+ *
+ * Check whether store is backed by a rotational (HDD) or non-rotational
+ * (SSD) device.
+ *
+ * This must be usable *before* the store is mounted.
+ *
+ * @return true for HDD, false for SSD
+ */
+ virtual bool is_rotational() {
+ return true;
+ }
+