Index: head/lib/geom/mirror/gmirror.8
===================================================================
--- head/lib/geom/mirror/gmirror.8
+++ head/lib/geom/mirror/gmirror.8
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 30, 2017
+.Dd June 9, 2019
 .Dt GMIRROR 8
 .Os
 .Sh NAME
@@ -31,7 +31,24 @@
 .Nm gmirror
 .Nd "control utility for mirrored devices"
 .Sh SYNOPSIS
+To compile GEOM_MIRROR into your kernel, add the following lines to your kernel
+configuration file:
+.Bd -ragged -offset indent
+.Cd "options GEOM_MIRROR"
+.Ed
+.Pp
+Alternatively, to load the GEOM_MIRROR module at boot time, add the following line
+to your
+.Xr loader.conf 5 :
+.Bd -literal -offset indent
+geom_mirror_load="YES"
+.Ed
+.Pp
+Usage of the
 .Nm
+utility:
+.Pp
+.Nm
 .Cm label
 .Op Fl Fhnv
 .Op Fl b Ar balance