Plex server runs at 100% load after scanning movie folder when I add a new movie.. thumbnails?

Crappy title sorry, I was too limited on space.

I’ve noticed for the last few months, any time I add a new movie to the server and then re-scan my movie folder to update the library, my Plex server fans spin up to max speed, and htop shows 100% CPU load.. and it lasts for a very long time.

Note: Nobody is watching anything on my server at the time of the screenshot, the file from my process list is the same file I just added to the server before re-scanning.

I THINK what it’s doing, is scanning the new movie file and creating thumbnails used for fast-forwarding during playback. I don’t know for sure, this is just an assumption.

  1. This should NOT happen immediately after scanning a folder! If Plex is going to run a process like this that can take 30+ minutes to run and pegs the CPU at 100%, this needs to be included in the “Scheduled Tasks” so it can be done overnight or during off-peak hours. If I add 5 new movies, this process can take hours of non-stop processing.

  2. Why on earth does this take so long and so much processing power? It looks to me based on the system process info (see screenshot), that Plex is transcoding the movie as it scans the file, which seems ridiculous if it’s just gathering thumbnails. This seems like something that should use relatively minimal resources, and should be scanning the original raw file.

Can I get some clarification why this is happening.. whether my thumbnail theory is correct or if it’s something else.

I would really love to see something done about this. I run my plex server on an Intel NUC, which is adequately powerful for 3 or 4 simultaneous 1080p transcoded streams.. but this process absolutely craps all over the CPU because it doesn’t transcode in segments like client streams do (throttled transcoding).

Pretty sure it is thumbs.
Simply Disable them or set them to be only created buring maintenance hours.
https://support.plex.tv/articles/202197528-video-preview-thumbnails/

@OttoKerner said:
Pretty sure it is thumbs.
Simply Disable them or set them to be only created buring maintenance hours.
https://support.plex.tv/articles/202197528-video-preview-thumbnails/

Oh, no wonder I couldn’t find it. I expected that option to be in Settings > Server > Scheduled Tasks but it isn’t there. You have to go to Settings > Library > Generate thumbnails > As a Scheduled Task. Confusing

Thanks! I just turned it on, so that shouldn’t drive me quite as nuts now.

Although I still don’t see why Plex needs to run the transcoder to generate thumbs. It has all the necessary codecs built in to read raw video files, it makes a LOT more sense to me to capture thumbs in raw rather than making the CPU run full tilt transcoding the video.