How to Limit Upload Speed in aria2c on Ubuntu

This guide explains how to control your bandwidth usage while seeding torrents with aria2c on Ubuntu. You will learn the specific command-line flags and configuration options needed to set a maximum upload speed. Following these steps ensures your internet connection remains stable for other tasks while sharing files.

Using Command Line Flags

To limit the upload speed directly when starting a torrent, use the --global-max-upload-limit option. This setting caps the total upload speed for all active torrents. You can specify the speed using K for kilobytes per second or M for megabytes per second.

Run the following command in your terminal:

aria2c --global-max-upload-limit=100K --seed-time=0 your-torrent-file.torrent

In this example, the upload speed is restricted to 100 kilobytes per second. If you need to limit the speed for a specific torrent rather than globally, use the --max-upload-limit flag instead.

Using the Configuration File

For a permanent solution that applies every time you run aria2c, edit the configuration file. This method prevents you from typing the limit flags manually for each session.

1. Open or create the configuration file located at ~/.aria2/aria2.conf.
2. Add the following line to the file:

global-max-upload-limit=100K

3. Save the file and restart any running aria2c sessions.

This setting ensures that aria2c never exceeds the defined upload bandwidth on your Ubuntu system unless overridden by a specific command-line argument.