Huge disk IO performance issue in Docker

[Gerben321]

I've asked on Reddit about it, but not answers. I'm seeing HUGE HDD read speeds on my Synology NAS with the Jellyfin Docker image. There are two modest libraries added for movies and series, and I've disabled the watcher. Was looking like a nice package in the start, but I've had several times that my whole NAS started to freeze. Here's the original post with info and a screenshot: https://www.reddit.com/r/jellyfin/comments/igjkh0/high_disk_read_speeds_with_jellyfin_in_docker/

Today I've seen 220mb/s read speeds. I then shut down the Docker container and the system went back to normal. Any idea why this is? It's really starting to become a showstopper which forces me back to a MySQL database for Kodi.

[Artiume]

It might be related to this fellow
#2355

[Gerben321]

I don't seem to have any ffmpeg references in my logs.

I do see a lot of errors like this one:

[2020-09-20 20:06:00.639 +00:00] [ERR] [121] MediaBrowser.Providers.TV.EpisodeMetadataService: Error in "The Open Movie Database"
System.NullReferenceException: Object reference not set to an instance of an object.
at MediaBrowser.Providers.Plugins.Omdb.OmdbProvider.FetchEpisodeData[T](MetadataResult1 itemResult, Int32 episodeNumber, Int32 seasonNumber, String episodeImdbId, String seriesImdbId, String language, String country, CancellationToken cancellationToken) at MediaBrowser.Providers.Plugins.Omdb.OmdbEpisodeProvider.GetMetadata(EpisodeInfo info, CancellationToken cancellationToken) at MediaBrowser.Providers.Manager.MetadataService2.ExecuteRemoteProviders(MetadataResult1 temp, String logName, TIdType id, IEnumerable1 providers, CancellationToken cancellationToken)

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[ssamjh]

This is still a massive problem. My entire server becomes unresponsive due to the high IO, I purchased an NVME SSD and it made no difference.

I have discovered two workarounds.

1. If you are using CPU encoding, enable the "throttle transcodes" options. Option 2 can also be applied for an extra boost.
2. If using a GPU then the "throttle transcodes" option does not work (see Throttle Transcode doesnt work #2919). Create a RAMDISK and pass that through to the VM as detailed here: https://forum.jellyfin.org/t/transcoding-to-ram/174/4