Hello ksabr, thanks for the detailed writeup and the kind words on the power supply, glad it's been solid otherwise!
So what you're running into is a known quirk with the ASM235CM bridge chips themselves (not unique to us, other enclosures using the same ASMedia chipset run into this too). Basically the chips can report duplicate UniqueIDs to Windows, and Storage Spaces is pretty strict about needing unique IDs before it'll pool drives together. ZFS doesn't care about this since it writes its own GUIDs, which is why you're not seeing any issue there.
We don't have a public firmware fix for this on the DS-SC5B yet, but let me flag this internally with our support team so we can get you a proper answer on whether a bay specific firmware update is possible. I'll follow up here once I hear back.
In the meantime, a couple of workarounds:
StableBit DrivePool is a solid alternative to Storage Spaces. It pools at the volume level instead of relying on hardware disk IDs, so this issue won't affect it at all.
Another thing you can try until it's resolved, you could also just run the drives as standalone volumes, or stick with something like ZFS/mdadm that generates its own disk identifiers instead of trusting the enclosure's reported ones.
Thanks for your patience. I will circle back with an update soon!
Sabrent Admin
