joshuaboniface / vmtouch-jellyfin-media

Quick and dirty tool for pinning playing media to memory (Linux)

vmtouch-jellyfin-media

This tool is designed to force media files opened with Jellyfin into resident memory using the vmtouch utility.

This can have numerous uses:

1. Avoid dying mid-stream if storage is flaky/blocks.

2. Allow faster skipping around the file.

3. Mitigate (some, but very little!) hard drive load.

In my case, #1 (a Ceph cluster that could block reads) is the primary goal.

This script is a really quick and dirty hack. It is specific to my particular install, but I'm providing it as a useful jumping-off point for others who might want to do something similar.

Prerequisites

• Requires Python 3 with several standard libraries (subprocess, threading, signal, re)

• Requires Jellyfin running as a standard operating system process outputting to journald.

• Requires the vmtouch tool installed and operational.

Usage

1. Copy the vmtouch-jellyfin-media binary to /usr/local/sbin/

2. Optionally, adjust the TOUCH_TYPE variable if you want to use a non-blocking lock.

3. Copy the vmtouch-jellyfin-media.service service unit to /etc/systemd/system/

4. Run sudo systemctl daemon-reload to reload the systemd configuration

5. Run sudo systemctl enable --now vmtouch-jellyfin-media to enable and start the program

It will then continually watch the Jellyfin service output (via journalctl) and act when it sees a file opened for playback. Upon opening, the file will be read into memory with vmtouch until playback of that file stops, at which time it will release the file from memory.

Caveats/Limitations

1. Needs systemd/journalctl in its current iteration, but this could be modified.

2. Requires root privileges (for reading the journal, running vmtouch, etc.).

3. Only works with locally-opened files; does not work with tools like RFFmpeg.

4. If you stop playback, the file is purged from memory and must be re-read; this was a conscious design decision.