Index: sys/geom/geom_disk.c
===================================================================
--- sys/geom/geom_disk.c
+++ sys/geom/geom_disk.c
@@ -549,6 +549,8 @@
                    indent, dp->d_fwheads);
                sbuf_printf(sb, "%s<fwsectors>%u</fwsectors>\n",
                    indent, dp->d_fwsectors);
+               sbuf_printf(sb, "%s<rotationrate>%u</rotationrate>\n",
+                   indent, dp->d_rotation_rate);
                if (dp->d_getattr != NULL) {
                        buf = g_malloc(DISK_IDENT_SIZE, M_WAITOK);
                        bp = g_alloc_bio();