Automatically fills a Lancache with games from Steam, so that subsequent downloads for the same content will be served from the Lancache, improving speeds and reducing load on your internet connection.
- Select apps to prefill through an interactive menu.
- Supports login with Steam Guard, and Steam Guard Mobile Authenticator
- No installation required! A completely self-contained, portable application.
- Multi-platform support (Windows, Linux, MacOS, Arm64)
- High-performance! Downloads are significantly faster than using Steam, and can easily reach 10gbit/s or more!
- Game downloads write no data to disk, so there is no need to have enough free space available. This also means no unnecessary wear-and-tear to SSDs!
- Completely implemented from scratch, has no dependency on
SteamCMD! - No Steam API key required!
Note New to Linux? See this detailed tutorial : Install Guide For Linux Beginners
Note Interested in using Docker instead? See : Docker Setup Guide
Note Using Unraid? See : Unraid Setup Guide
- SteamPrefill can be run on both the Lancache server itself, or on your gaming machine as an alternative Steam client. You should decide which one works better for your use case.
- Download the latest version for your OS from the Releases page.
- Unzip to a directory of your choice
Warning Linux and macOS will require executable permissions to be granted with
chmod +x ./SteamPrefillprior to running the app.
Note Alpine Linux requires additional dependencies to be installed for the .NET runtime : Alpine Linux Dependencies
Configuring your terminal to use Unicode will result in a much nicer experience with SteamPrefill, for much nicer looking UI output.
As the default console in Windows does not support UTF8, you should instead consider installing Windows Terminal from the Microsoft App Store, or Chocolatey.
Once Windows Terminal has been installed you will still need to enable Unicode, as it is not enabled by default. Running the following command in Powershell will enable it if it hasn't already been enabled.
if(!(Test-Path $profile))
{
New-Item -Path $profile -Type File -Force
}
if(!(gc $profile).Contains("OutputEncoding"))
{
ac $profile "[console]::InputEncoding = [console]::OutputEncoding = [System.Text.UTF8Encoding]::new()";
& $profile;
}Warning This guide was written with Linux in mind. If you are running SteamPrefill on Windows you will need to substitute
./SteamPrefillwith.\SteamPrefill.exeinstead.
Prior to prefilling for the first time, you will have to decide which apps should be prefilled. This will be done using an interactive menu, for selecting what to prefill from all of your currently owned apps. To display the interactive menu, run the following command
./SteamPrefill select-appsOnce logged into Steam, all of your currently owned apps will be displayed for selection. Navigating using the arrow keys, select any apps that you are interested in prefilling with space. Once you are satisfied with your selections, save them with enter.
These selections will be saved permanently, and can be freely updated at any time by simply rerunning select-apps again at any time.
Now that a prefill app list has been created, we can now move onto our initial prefill run by using
./SteamPrefill prefillThe prefill command will automatically pickup the prefill app list, and begin downloading each app. During the initial run, it is likely that the Lancache is empty, so download speeds should be expected to be around your internet line speed (in the below example, a 300mbit/s connection was used). Once the prefill has completed, the Lancache should be fully ready to serve clients cached data.
Updating any previously prefilled apps can be done by simply re-running the prefill command, which will use same prefill app list as before.
SteamPrefill keeps track of which version of each app was previously prefilled, and will only re-download if there is a newer version of the app available. Any apps that are currently up to date, will simply be skipped.
However, if there is a newer version of an app that is available, then SteamPrefill will re-download the app. Due to how Lancache works, this subsequent run should complete much faster than the initial prefill (example below used a 10gbit connection). Any data that was previously downloaded, will be retrieved from the Lancache, while any new data from the update will be retrieved from the internet.
You certainly can! All you need to do is download SteamPrefill onto the server, and run it as you reguarly would!
If everything works as expected, you should see a message saying it found the server at 127.0.0.1
Running from a Docker container on the Lancache server is also supported! You should instead see a message saying the server was found at 172.17.0.1
Running on the Lancache server itself can give you some advantages over running SteamPrefill on a client machine, primarily the speed at which you can prefill apps.
Since there is no network transfer happening, the prefill should only be limited by disk I/O and CPU throughput.
For example, using a SK hynix Gold P31 2TB NVME and running prefill --force on previously cached game yields the following performance
Yes it can! Scheduled jobs can be easily setup on Linux using crontab, and can be flexibly configured to run on any schedule that you desire. Jobs are configured by specifying an "expression" that describes the schedule to run on.
Some examples of cron expressions:
| Schedule | Cron Expression |
| Every day at 2am |
|
| Every 4 hours |
|
If the above examples don't cover your use case, crontab.guru is an online cron expression editor that can interactively edit cron expressions, and explain what they mean.
Once you have determined a cron expression, you can then create a job using the following:
Note This command should be run in the same directory where SteamPrefill is installed
job="cron expression here"; { crontab -l; echo "$job"; } | crontab -
After running the command, you can verify that the job was successfully created with crontab -l. If the output matches below, then your job is correctly configured!
Unfortunately it is not possible to fill a Lancache using games that have been installed with Steam. The installed games are in a different format than what Lancache caches, as they are decrypted and unzipped from the raw request. The decryption/unzip process is not reversible. Thus, the only way to get games properly cached is to redownload them using either SteamPrefill or Steam
You may want to limit the download speed of SteamPrefill to prevent it from potentially saturating your entire connection, causing other devices to suffer from massive latency and poor speeds. This issue is known as bufferbloat, and more detailed information on the issue can be found here: What is bufferbloat?
SteamPrefill does not currently contain any functionality to limit its own download speed, and due to the way that downloads are implemented will likely never be able to throttle its own download speed. Additionally, even if SteamPrefill was able to throttle itself, the same issue would persist with downloads through Steam.
One method to limit bandwidth would be to configure Quality of Service (QOS) on your router, limiting bandwidth to the Lancache server, or by prioritizing other network traffic. A general overview of QOS can be found here : Beginners guide to QOS
For more brand specific guides (non-exhaustive), see :
Note Detailed command documentation has been moved to the wiki : Detailed Command Usage
SteamPrefill will automatically check for updates, and notify you when an update is available :
- Windows
- Run the
.\update.ps1script in the executable directory
- Run the
- Linux
- First time only : Grant executable permissions to the update script with
chmod +x ./update.sh - Run the
./update.shscript in the executable directory
- First time only : Grant executable permissions to the update script with
- Download the latest version for your OS from the Releases page.
- Unzip to the directory where SteamPrefill is currently installed, overwriting the previous executable.
- Thats it! You're all up to date!
- sudo docker pull tpill90/steam-lancache-prefill:latest
If you are running into any issues, feel free to open up a Github issue on this repository.
You can also find us at the LanCache.NET Discord, in the #steam-prefill channel.
- @dlrudie for all your help with debugging and testing!