So a friend of mine had TerraMaster F5-221 that he did not need anymore so I took it off his hands. I was thinking of using it as a remote NAS for family and started to look into what could be done with it.
Specs:
Intel® Celeron® J3355
Upgraded to. 10GBs of Memory
Dual 1GE Ethernet adapters ( Realtek )
HDMI Video
2 x USB 3.0 external
2 x USB 2.0 internal
64GB USB 3.0 Boot device
After playing with TerraMaster OS if found it to be a bit of a kludge and of course thought "Why not try running OMV!?"
After a little bit of research it appears that others have gotten OMV to run on this device. I could find references to OMV 4 being installed but nothing more recent, at least not that I could find.
Having just upgraded my "play server" to OMV 6 I thought, "Why not try that on the F5-221?". I downloaded the install OMV 6 image popped it on a thumb drive and then hooked up a USB hub so I could use a kybd, boot USB and my target USB thumb drive.
Under the Startup section of the BIOS I changed the following:
Full Screen Logo Show: Disabled
Boot Options Filter: UEFI Only
Video: UEFI Only
Other PCI Devices: UEFI Only
Once I restarted the device it saw the installation USB and begin the install process. I selected my 64GB USB thumb drive as the target and off it went and soon I had a new OMV 6 bookshelf NAS. 
There are only a few gotchas when it comes to running OMV on this hardware, that others have mentioned.
1) The sensors are uses a very old chip that does not have a mainstream driver, my box is running an it8613E chip.
2) The LEDs are driven by a custom driver from TerraMaster and will do nothing without this driver.
Luckily there are work arounds for these two issues.
Item 1:
There was a driver released that may work with this chip, however the author has removed the driver from GIT but there are a couple mirrors of his repo.
https://github.com/a1wong/it87
https://github.com/hannesha/it87
I have not gotten either of these to work reliably, but I am also not great with Linux drivers and am still working to get one of these working.
Fortunately you can also configure the fans in the BIOS to run all the time and they are not too loud.
Under Advanced -> H/W Monitor -> System Fan Mode Setting: Full on Mode
There is this item that is supposed to allow you to control the fans, but I have not had time really work on it as my sensor drive is not loading at boot so I need that working first.
https://github.com/ahmedmagdiosman/terramaster-fancontrol
Item 2:
There is a driver that has been developed that will let you echo a value to each led driver to set the color.
You can find that driver here;
https://github.com/arnarg/hddled_tmj33.
With this driver you can not turn the LED on, make it Green, Red, or Orange, or turn it off.
My next step is to try and develop a script or something to will check the smart status of any drives installed and change the LED for the drive to the appropriate color.
I am looking into smartcontrol which is what OMV uses to provide the S.M.A.R.T status for drives. The script that has been developed for OMV is really nice and provides a few different cases of drive health. Unfortunately I am not a developer and while I can sort of follow the PHP script that I found my lack of basic understanding on PHP is limiting me.
A version of the script that OMV provides is HERE.
My goal is to hopefully leverage this script, or at least the logic within it to send the appropriate commands to the LED drivers so the indicator matches the S.M.A.R.T. status in the OMV Dashboard.
As drives can change devices based upon what slot they are within the system, 2 drives vs 5 drives I need to leverage lsscsi to match the "Slots" to the drives. We can not assume the /dev/sdb is always in slot two and do not want to set the wrong LED to the wrong color. 
root@tmvomv6:~$lsscsi
[0:0:0:0] disk ATA SNXXXX /dev/sda
[1:0:0:0] disk ATA SNXXXX /dev/sdb
[2:0:0:0] disk ATA SNXXXX /dev/sdc
[3:0:0:0] disk ATA SNXXXX /dev/sdd
[6:0:0:0] disk USB SanDisk 3.2Gen1 1.00 /dev/sde
As I am not a developer this will certainly take me some time to work through and welcome any insights or information others may wish to offer. So far this little box has been fun to play with and work through and hopefully others will find this information useful.