I noticed my home servers SSD running out of space and it ended up being my Jellyfin Docker container which wasn’t clearing the directory for transcodes in /var/lib/jellyfin/transcodes correctly.
I simply created a new directory on my media hard drive and bind mounted the above mentioned directory to it. Now Jellyfin got over 1 TB of free space to theoretically clutter. To prevent this I simply created a cronjob to delete old files in case Jellyfin isn’t.
/usr/bin/find /path/to/transcodes -mtime +1 -delete
Easy!
Can just point it to /dev/shm as a transcoding folder, for a quick and dirty way.
Otherwise you’d mount a tmpfs disk.