At last Multipath (with a few quirks)

[KenwoodFox]

For ages, I've been having issues with multipath working, all a sudden, AHA! My missing multipath option just appeared after I installed another drive into my system!

Ureka!
While this is good and all, that it finally showed up, only one drive is listed as multipath.
The rest are still just duplicated. Now that this tab shows up, what is my next step?

 

[KenwoodFox]

Interestingly, I added another spare drive, and now two disks appear?..

 

[KenwoodFox]

I think I'm uncovering clues perhaps.
My spares were auto-discovered, I tried using gmultipath but I get this result on a drive in the pool.

Code:

# gmultipath label name da20
gmultipath: cannot store metadata on da20: Operation not permitted.

perhaps multipath can only work with disks that are not in a pool?