diff --git a/site/profiles/manifests/base/datavol.pp b/site/profiles/manifests/base/datavol.pp
index 2d3fb37..167f60a 100644
--- a/site/profiles/manifests/base/datavol.pp
+++ b/site/profiles/manifests/base/datavol.pp
@@ -7,7 +7,7 @@
 #   $vg       - Volume group name. No default.
 #   $pv       - Physical volume, typically the disk or partition device path. No default.
 #   $fstype   - Filesystem type for the logical volume. Defaults to 'ext3'.
-#   $size     - Size of the logical volume. No default.
+#   $size     - Size of the logical volume. undef = 100%FREE. Changing $size to cause a resize.
 #
 class profiles::base::datavol (
   Enum['present', 'absent'] $ensure = 'present',
@@ -16,7 +16,7 @@ class profiles::base::datavol (
   String $pv = '/dev/vdb',
   String $lv = 'data',
   Stdlib::Absolutepath $mount = '/data',
-  Variant[Pattern[/^[\d+GTP%FREE]$/], Integer] $size = '100%FREE',
+  Optional[Variant[Pattern[/^\d+(M|G|T|P)$/], Integer]] $size = undef,
   Array  $mount_options = ['noatime', 'nodiratime'],
 ) {