I have one array disk that refuses to spin down, if I manually spin it down it immediately spins back up.  The same problem exists for the parity drive in the array.  I installed the File Activity plugin and it shows no activity.  The system log only shows the following:

 

Nov 20 10:22:54 snarf  emhttpd: spinning down /dev/sdh
Nov 20 10:22:56 snarf  emhttpd: read SMART /dev/sdh
Nov 20 10:23:29 snarf  emhttpd: spinning down /dev/sdd
Nov 20 10:23:31 snarf  emhttpd: read SMART /dev/sdd

 

Any thoughts of where to look / what to do next?

Only reason for a drive to spin back up is that a read is currently happening for it.  If the parity also spins back up at the same time, then a write is happening to that data drive.

 

In terms of why, the first guess is that your docker image file (or folder) is sitting on a data disk.  Alternatively, your appdata share is on a data drive.

 

Additionally, if you're running NextCloud / Owncloud then due to their own designs, any disk which is a member of its media shares will always stay spinning.

Hi Squid, thanks for the helpful tips.  The docker image file was in fact on an array disk and my libvirt folder was also on a disk.  Unfortunate that these don't show up with the Open Files and File Activity plugins.  Was able to move my system share to an SSD cache and all is good now.  It's worth noting for anyone else reading this if you don't have a redundant cache you might not want to move these files to a cache drive as there is a risk of data loss with a single SSD failure.