I almost Have the same problem ,my DL4100 start making noise and works too hard on its own without me using PC or using plex ,and all 4 drives are working at the same time ,since i configured it JBOD its kinda strange.
I have DL4100 and I also have PleX like you,So my problem started a few days ago after i linked my DL4100 to my PC through Plex to watch movie and tv shows
the only reason i bought this was use it for Plex ,I use my PC as server i think and DL4100 as network storage.
as far as i know i have closed all remote and outside private network access to both my Plex and NAS
I am not very good at this stuff ,but i think Plex use DL4100 to read the media and send it to PC to be processed and then send the image to TV .
I could be wrong because i just bought it 2-3 day before linked it with plex so i don’t know much how it usually behaves
but some time it starts sending data to my PC and at full network capacity on it’s own ,without me using DL4100 or Using Plex to watch something storet on DL4100.
if i don’t turn it off it will continue to send 100s of Giga byte to some where or my PC , in fact at this time I can’t copy anything to the DL4100 because my home network bandwidth is full.
in Windows task manager ,Performance tab shows i am receiving huge amount of data.
I have LAN 1000 and wireless 600 and slow internet connection , in fact the amount of data send by DL4100 to god knows where is 100 times my internet contention bandwidth so i don’t think that some one stealing my Data or hacked me through internet.lets say i have 10mbs internet connection from my ISP but i am sending 500 mbs data through my private network
but it may be possible someone nearby hacked my WiFi however i couldn’t find any strange IP connected to my Wifi.
some one please for love of god solve this problem ,
at this point if you tell me My NAS DL4100 is is alive or possessed by a ghost i might believe you ( i have supernatural tv show stored in it so its possible)