Maybe someone can tell me why this is happening...
My Unraid server crashed today. I'm running Emby in Docker.
When I tracked the problem down, it was because I ran out of space on my 1TB cache drive. A little more digging led me to the transcoding-temp directory of Emby which is stored on the cache drive. There were almost 800K files totalling over 500GB of space. The files go back to May of 2019.
A large file transfer caused the drive to fill up the rest of the way, and then