Put shared hard drive to idle on OpenWrt

 There are two applications to put a hard drive to idle in Openwrt:

1. HDD Idle (hd-idle): This option did not work for me.
2. HD Parm (hdparm): This option worked perfectly, here is the command to use:

hdparm -S 24 /dev/sdb1

The previous command stops the disk from spinning after 2 minutes.