Plex and Cache migration

I just bought a 'Plus' licence and proceeded to move my Plex data files from the data drive onto the cache. This wasn't easy and in the process I lost the indices and so I setup a new directory and let Plex populate the data from scratch. The next goal was to get unRaid not to spin the data and parity drives except when called on by the mover or for reads to match media playing. I also installed the Folder Caching  plug-in to keep directory data in memory.

I could not get the drives to spin down for any significant period of time so here is a list of things that tripped me up.

Firstly I didn't understand the share setting Yes/No/Cache Only. I had set the Plex share to Cache only 'cos that is in the list of instructions BUT nowhere does it tell you that your media shares need to have the setting set to Yes. Anyway when that was resolved the drives still didn't spin down. (I do think some explanatory text next to this drop-down would help)

The next issue seemed to be that if I had the Media drive just mounted on my Mac then every thirty seconds the drives were accessed. So I unmounted the media. Still not resolved and anyway not really what I want.

Anyway I'd forgotten about Time Machine so that was disabled too but still my drives are accessed.

Today logged in as 'root' and deleted the remaining left over Plex index files. Somewhere there had been a permission problem and some files claimed to be in use. That bit is weird. I had already tried stopping Plex and restarting the unRaid array. Nothing else allowed me to delete them. At last the drives aren't being accessed every thirty seconds and I re-instated the mounted Media drive and that's no longer a problem but I notice that the network and CPU have fun every 15 seconds so I guess that the directory cache is doing its job?

Finally I have reinstated Time Machine and set the share with the Cache = Yes status.

I'm not yet convinced I've got it all fixed but its hugely better. I really don't see what was going on with the old Plex indices, maybe somewhere there is some config data that isn't reset when you change the Library and Temp pointers in Preferences.

Edit: Well still not happy. Stopping Time Machine has stopped some regular accesses that re-appeared. So still trying to solve this.