How to install Transmission on Raspberry Pi (with external storage)

Well there are already many guides on this topic, however, what I found is not all are in complete detail, or misses out on something of the other (completely personal opinion though :) ). Here comes my guide to install Transmission BitTorrent client on headless Raspberry Pi. This will especially be helpful for users who have followed my guides on setting up NAS drive with RasPi.

Let's Start...

Step 1
Install transmission
sudo apt-get update
sudo apt-get install transmission-daemon

Step 2
Create required directories on your NAS storage (path to storage is assumed as /media/NASDRIVE)
mkdir -p /media/NASDRIVE/Torrent_inprogress
mkdir -p /media/NASDRIVE/Torrent_complete

Step 3
Permissions
Transmission by default runs with user "debian-transmission", as it is recommended not to change this due to security reasons. In our setup the NASDRIVE has the permission set as 770 for pi : pi. Thus we will add user "debian-transmission" to "pi" group to give rwx access on our NASDRIVE. You can go ahead and modify this step as per your security requirement, but just make sure your torrent download directories are having rw access for "debian-transmission" user.
sudo usermod -a -G pi debian-transmission

Step 4
Configure Transmission
While most of the parameters are self explanatory in the conf file, you can use the file given below, except for modify the parameters download-dir, incomplete-dir, rpc-username, rpc-password 
Note: rpc-password will automatically converted to hashstring on saving the file
sudo nano /etc/transmission-daemon/settings.json

	{
	"alt-speed-down": 15,
	"alt-speed-enabled": false,
	"alt-speed-time-begin": 540,
	"alt-speed-time-day": 127,
	"alt-speed-time-enabled": false,
	"alt-speed-time-end": 1020,
	"alt-speed-up": 15,
	"bind-address-ipv4": "0.0.0.0",
	"bind-address-ipv6": "::",
	"blocklist-enabled": true,
	"blocklist-url": "http://list.iblocklist.com/?list=ydxerpxkpcfqjaybcssw&fileformat=p2p&archiveformat=gz",
	"cache-size-mb": 4,
	"dht-enabled": true,
	"download-dir": "/media/NASDRIVE/Torrent_complete",
	"download-limit": 100,
	"download-limit-enabled": 0,
	"download-queue-enabled": true,
	"download-queue-size": 5,
	"encryption": 1,
	"idle-seeding-limit": 30,
	"idle-seeding-limit-enabled": false,
	"incomplete-dir": "/media/NASDRIVE/Torrent_inprogress",
	"incomplete-dir-enabled": true,
	"lpd-enabled": false,
	"max-peers-global": 200,
	"message-level": 2,
	"peer-congestion-algorithm": "",
	"peer-limit-global": 240,
	"peer-limit-per-torrent": 60,
	"peer-port": 51413,
	"peer-port-random-high": 65535,
	"peer-port-random-low": 49152,
	"peer-port-random-on-start": false,
	"peer-socket-tos": "default",
	"pex-enabled": true,
	"port-forwarding-enabled": true,
	"preallocation": 1,
	"prefetch-enabled": 1,
	"queue-stalled-enabled": true,
	"queue-stalled-minutes": 30,
	"ratio-limit": 2,
	"ratio-limit-enabled": false,
	"rename-partial-files": true,
	"rpc-authentication-required": true,
	"rpc-bind-address": "0.0.0.0",
	"rpc-enabled": true,
	"rpc-password": "{46949fbf39bfeec6dc9d4bff9f40c3f52219a4260yk9yGNo",
	"rpc-port": 9091,
	"rpc-url": "/transmission/",
	"rpc-username": "transmission",
	"rpc-whitelist": "127.0.0.1",
	"rpc-whitelist-enabled": false,
	"scrape-paused-torrents-enabled": true,
	"script-torrent-done-enabled": false,
	"script-torrent-done-filename": "",
	"seed-queue-enabled": false,
	"seed-queue-size": 10,
	"speed-limit-down": 100,
	"speed-limit-down-enabled": false,
	"speed-limit-up": 100,
	"speed-limit-up-enabled": false,
	"start-added-torrents": true,
	"trash-original-torrent-files": true,
	"umask": 7,
	"upload-limit": 100,
	"upload-limit-enabled": 0,
	"upload-slots-per-torrent": 14,
	"utp-enabled": true
	}

view raw settings.json hosted with ❤ by GitHub

Step 5
Reload Transmission
Do not restart, It overwrites the configuration file in that case
sudo service transmission-daemon reload

Step 6
Open web browser and hit http://your_raspberry_pi_IP:9091
Enter the user id and password you've configured, and viola!