SOLVED: Jellyfin becomes unresponsive when transcoding

[Henkow]

My only other suggestion is to look through syslog or something for any system related errors.

well it's nothing to do with running out of ram, processor usage or disk failing everything looks normal (good even)

i wonder how much can be diagnosed on the client side (firefox) seems it's either that or a TCP thing

i don't have anything further to suggest on this

I did try to transcode to ramdisk instead and while I couldn't get quite far enough in the movie where it would usually freeze (before running out of ram), a new tab did load. So there must be something with the access to the SSD. I tried upgrading my SMB share to v3 and connected my PC straight to the same switch as the server, bypassing the router, to see if something would change but got the same behaviour. I have other docker containers that occasionally want to access the SSD (mainly HA and Adguard), but surely that shouldn't be noticeable?
 
As a last resort I enabled throttle transcoding. When I tried this last year it didn't work well for me but now it works great and appears to fix everything. The Web UI stays responsive and I just tested 4 streams concurrently, 3 out of which needed the video transcoded as well. No buffering at all. I'm suprised this work as a lot of transcoding takes place in the beginning regardless if the transcoding is throttled or not. While I would like to get to the bottom of this eventually, I think I'll stick with this for now.

Thanks for all the suggestions, will keep using iotop!