diff --git a/puppet-manifests/src/modules/platform/lib/facter/is_primary_disk_rotational.rb b/puppet-manifests/src/modules/platform/lib/facter/is_primary_disk_rotational.rb
index d80896f..599fcd8 100644
--- a/puppet-manifests/src/modules/platform/lib/facter/is_primary_disk_rotational.rb
+++ b/puppet-manifests/src/modules/platform/lib/facter/is_primary_disk_rotational.rb
@@ -1,6 +1,6 @@
 require 'facter'
 Facter.add(:is_primary_disk_rotational) do
-  rootfs_partition = Facter::Core::Execution.exec("df --output=source / | tail -1")
+  rootfs_partition = Facter::Core::Execution.exec('sed -e "s/^.*\(root=\)\(.* \).*$/\2/g" /proc/cmdline')
   rootfs_device = Facter::Core::Execution.exec("basename #{rootfs_partition} | sed 's/[0-9]*$//;s/p[0-9]*$//'")
   setcode "cat /sys/block/#{rootfs_device}/queue/rotational"
 end