Wardy

For anyone interested, I solved my IO wait issue by changing my cache fs to xfs. Everything's working as expected now!

I'm having issues with write cache overload / high IO wait. I used to own a seedbox, but then moved to a place with a gigabit line, so decided to bring everything in-house. I'm running on an array of 5x 4TB disks (~< 1 year old), with a 500GB SSD cache sitting on top. The server itself is an 8c/16t xeon with 64GB of ram. For some reason now, when I'm downloading large files, it'll hit max speed for a bit, then drop down to ~40MBs, and unraid UI will lock up. If I SSH in, top says my wait is 40-50, at the same time, qbt is reporting around 80% write cache overload. None of this seems particularly normal to me, and I would assume that any downloads go straight to the cache (considering that's where my docker image sits), so there should be no huge wait times there. I've tried different combinations of pre-allocating or not, playing with the IO threads and cache lifetime values, but I can't seem to figure out what the problem is here. If anyone has any idea where I can start looking, that would be amazing, thanks.