So just over a month ago I had a problem with one drive in the raid5, and whilst the replacement was rebuilding a second drive failed - so I lost the who raid 
I completely wiped the OMV system drive and rebuilt from scratch and only today noticed I hadn't set-up the notification email details page, and upon doing so received degraded notices on one of the drives.
Thing is the indicated faulty drive is one that I received as a new warranty replacement from WD for one of the original faulty units - so very unlikely would fail this quickly. Could I have a hardware issue with the SATA port or N36L hardware itself?