diff --git a/README.md b/README.md
index 46ebc246..da4cc9ca 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,10 @@ following in your devstack `local.conf`:
 ```
 [[local|localrc]]
 enable_plugin nova-lxd https://git.openstack.org/openstack/nova-lxd
+
+# You should enable the following if you use lxd 3.0.
+# In addition, this setting requires zfs >= 0.7.0.
+#LXD_BACKEND_DRIVER=zfs
 ```
 
 Change git repositories as needed (it's probably not very useful to point to the main
diff --git a/devstack/local.conf.sample b/devstack/local.conf.sample
index d4547423..41ff1ab7 100644
--- a/devstack/local.conf.sample
+++ b/devstack/local.conf.sample
@@ -22,3 +22,6 @@ disable_service n-net
 
 # enable nova-lxd
 enable_plugin nova-lxd https://git.openstack.org/openstack/nova-lxd
+# You should enable the following if you use lxd 3.0.
+# In addition, this setting requires zfs >= 0.7.0.
+#LXD_BACKEND_DRIVER=zfs