diff --git a/etc/nova/nova.conf.sample b/etc/nova/nova.conf.sample
index e8ebf5fc5956..73115f93b8b9 100644
--- a/etc/nova/nova.conf.sample
+++ b/etc/nova/nova.conf.sample
@@ -2052,7 +2052,7 @@
 #xen_hvmloader_path=/usr/lib/xen/boot/hvmloader
 
 # Specific cachemodes to use for different disk types e.g:
-# ["file=directsync","block=none"] (list value)
+# file=directsync,block=none (list value)
 #disk_cachemodes=
 
 # Which pcpus can be used by vcpus of instance e.g:
diff --git a/nova/virt/libvirt/driver.py b/nova/virt/libvirt/driver.py
index 6c91f78780b2..266dbcf103eb 100644
--- a/nova/virt/libvirt/driver.py
+++ b/nova/virt/libvirt/driver.py
@@ -213,7 +213,7 @@ libvirt_opts = [
     cfg.ListOpt('disk_cachemodes',
                  default=[],
                  help='Specific cachemodes to use for different disk types '
-                      'e.g: ["file=directsync","block=none"]'),
+                      'e.g: file=directsync,block=none'),
     cfg.StrOpt('vcpu_pin_set',
                 help='Which pcpus can be used by vcpus of instance '
                      'e.g: "4-12,^8,15"'),