I can see it needing to be compiled for the OS drive but I would think a module would work just fine for a data drive.
No idea. But please keep in mind that a lot of reports about disks spinning not up might be related to powering problems so reports without logs are useless anyway.
Since I'll stay away from here for some time (waiting for Hardkernel maybe able to fix some of the XU4 and Cloudshell issues and for more mature kernel support for Allwinner H3 and H5 boards, will ping you most probably soon when creating new EspressoBin and/or Clearfog images with kernel 4.11 since those are then the best ARM NAS boards around) just an overview of current situation with SBC that look promising from an OMV perspective if people are searching for a fast and energy efficient NAS:
https://forum.armbian.com/inde…findComment&comment=31957 (might take hours to read through since a lot of links are part of the overview with performance numbers and stuff like that)