Transmission is a solid torrent downloader daemon which has a nice web UI and it's really simple to operate.

There are also other tools like qBitTorrent and Deluge for the first one requires a GUI to be installed, and i don't have any X related packages on my server, while the second one just feels a bit outdated as UI, but still works fine.

Transmission is easily installed and managed within Gentoo linux since there is an ebuild for it. All you need to do is to emerge it:

emerge -v transmission

This step will create a dedicated transmission user but you will want to add it to the group media, that you have created before, so that the it will be able to access and manage your media collection:

usermod -a -G media transmission

Also, you want to move Transmission home folder under /data/daemons/transmission for consistency and to be protected on the RAID array. but since Gentoo decided that the transmission user doesn't have a real home, you need to move it manually:

mv /var/lib/transmission /data/daemons/transmission

then you need to change the user transmission runs under, this is to ensure that the other tools can fetch the downloads once complete. This is pretty easy, open the file /etc/conf.d/transmission-daemon and change the runas_user setting like this:

runas_user=transmission:media
config_dir==/data/daemons/transmission/config
download_dir=/data/daemons/transmission/downloads

Set also the correct folders.

One last required step is to ensure that the other tools can access the transmission folder (to reach the download folders inside), so:

chgrp media /data/daemons/transmission

Before you proceed, you should make Transmission accessible via the reverse-proxy, so that access, configuration and usage will be simplified from the beginning. Add this file to /etc/nginx/folders:

transmission.conf

# Transmission
location /transmission/ {
        proxy_pass http://127.0.0.1:9091;
}

Add this to your Reverse Proxy setup and restart it.

You need to change some default Transmission settings now, edit the file /data/daemons/transmission/config/settings.json and make sure to change the following settings:

   "download-dir": "/data/daemons/transmission/downloads",
   "rpc-url": "/transmission/",
    "rpc-bind-address": "127.0.0.1",

Where:

• download-dir: where the fully downloaded files will be moved
• rcp-url: the base-url where the Transmission web GUI is reverse-proxied
• rpc-bind-address: for security reasons, accept only local connections.

Now, setup the daemon to start at boot, and start it now:

 > rc-update add transmission-daemon default
 > /etc/init.d/transmission-daemon start

Every download client needs to be integrated in your other tools. Unfortunately, you need to do it by hand for every tool.

Every *Arr's tool has the same settings → downloaders section that you can populate with the downloaders. Tap on the plus button and add the downloader. Test it before saving.

Prowlarr is a special case: you only need to define the downloader IF you plan to search from the Prowlarr web GUI, otherwise it's not needed. And no, Prowlarr will not synchronize your downloader to the other *Arr's, like it's done for indexers. Sad, but that's the way it is.

Head to 192.168.0.1/transmission from which you add your manual downloads or manage the automatic downloads added by the other tools.