Implementation of script and service unit

hd-standby

@@ -0,0 +1,29 @@
+#! /bin/bash -eu
+
+# set rotational disks to spin down after a timeout
+
+DISK_NAME=${1:?disk name required}
+
+# default delay: 10 mins
+DELAY=${2:-120}
+
+function resolve_disk {
+    for devpath in "$1" "disk/by-id/$1" "disk/by-path/$1"; do
+        if [ -b "/dev/$devpath" ]; then
+            abspath=$(readlink -f "/dev/$devpath")
+            echo ${abspath#/dev/}
+            return
+        fi
+    done
+    echo "No disk named '$1' found" >/dev/stderr
+    return 1
+}
+
+DISK=$(resolve_disk "$DISK_NAME")
+
+if [ $(cat /sys/block/$DISK/queue/rotational) == 0 ]; then
+    echo "Not a rotating disk: $DISK" >/dev/stderr
+    exit 1
+fi
+
+hdparm -S $DELAY /dev/$DISK

hd-standby@.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=Spindown timeout for rotating disk %i
+After=suspend.target hibernate.target
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/usr/sbin/hd-standby %i
+ExecStop=/usr/sbin/hd-standby %i 0
+
+[Install]
+WantedBy=basic.target suspend.target hibernate.target
+