I've found a fix for this. I plug a USB 3.0 pendrive (not powered) for just PLEX library, and in the other USB router port is plugged a 5 TB HDD with the media files that doesn't wake up.
You are right. HDD that have PLEX library metadata turns on every 5 minutes after going sleep mode. So now "sleep mode" works, but only If I disable PLEX AND DLNA SERVER. I guess there isn't any fix for this.. Anyway, thanks @kamoj
First time I use Kamoj Addon (latest build) mainly to get my both HDDs going sleep mode, but after the whole night with "Spin down" set to 60 minutes, this morning they are still on. Any suggest?
I've a R9000