I have installed an SSD cache drive and moved my appdata to it ("cache only").  I have Plex running from the appdata folder.  When I've spun the disks down and there is no demand on the machine, Plex is not updating anything, et cetera, it seems to me the HDs should remain spun down.  However, this doesn't appear to be the case: after a short while, the HDs are spun up again.

 

Is there some way I can find out what is causing the spin-ups?  I've had a quick look at the log, but I'm not really sure what I should be looking for.

 

Thanks in advance.

I'm not positive on this, but I think Plex has a sechedule mechanism in it that is on by default. It's very possible that it's scanning your disks for new shows and that's causing the spin up. Again I could be confused but I think it works that way.

 

If this is what is happening you can disable that in the plex settings.

I think I've fixed the obvious settings (e.g., don't poll the library, only refresh once per day, etc.).

 

I'm going to stop Plex, spin the drives down, then double check that the drives stay spun down.  That should at least tell me whether Plex really is the culprit.

Yup, it's Plex.  Well, off to the Plex forums now!

D'oh!  I am an idiot.  I'd left my docker.img on disk1, I had forgotten to move it to the cache drive when I installed it.  That now done, all is fixed.