1. Should show you what drives are there connected to the Raspberry Pi

sudo fdisk -l

2. Create a directory for the mount

mkdir /media/nas

3. Test by mounting the drive to the directory

sudo mount /dev/sda1 /media/nas

4. Edit the file /etc/fstab and add the following line to automount the dive on boot

/dev/sda1   /media/nas  ntfs-3g rw,default  0   0

Spindown external HDD

1. Find out the device names

sudo blkid

2. Install hdparam

sudo apt-get update
sudo apt-get install hdparm -y

3. Check for drive compatibility

Make sure your drive supports hd parm, if you have multiple hard drives it could be /dev/sda or /dev/sdb – the command blkid will show you all disk drives connected.

sudo hdparm -y /dev/sda1
sudo /usr/sbin/hdparm -y /dev/sda1

You should get output like this indicating a successful standby command

/dev/sda1:
 issuing standby command

Check if your drive supports write cache

sudo hdparm -I /dev/sda1 | grep 'Write cache'
sudo /usr/sbin/hdparm -I /dev/sda1 | grep 'Write cache'

If you see a * (asterix) then you are good to go.

*    Write cache

4. Use hdparam

To make hdparm spindown the device you can use the -B flag
Values between 1 and 127 allow spinning down of the hard drive.

sudo hdparm -B127 /dev/sda1

Time to make hdparm configurations permanent edit the configuration file /etc/hdparm.conf

The spindown_time value is multiplied by 5 and you have the total time in seconds. So a value of 120 yields 10 minutes (120*5=600).

Enable write cache and spindown time by adding this text to the bottom of the file

/dev/sda1 {
write_cache = on
spindown_time = 120
}

Restart the hdparm service

More hdparm configurations are available here.