Almost 3 years later.... I've returned to this thread looking for answers to go beyond the drive count limits.
I have a lot of drives. Maybe 60 or so. Presently I run UnRAID on bare metal, with two nested VMs that also run UnRaid. Tota of three UnRAID pro licenses to make this possible, each with their own USB key pass-thru to the VM. It's awesome and it works @limetech. The bare metal is 36 bay SuperMicro server with external SAS cards that attach to a SuperMicro JBOD array.
I want to add more drives. A lot more drives. I recently came into possession of 4 of those BackBlaze 45 drive storinators. The backplanes and SATA expanders can be mapped to two UnRAID instances. It'd be split with 30 disks to one UnRaid instance, and 15 to the other UnRAID. That 15 seem inefficent and is nagging at me to find something else to have a single 45 drive array.
What's the answer? I've been researching SnapRaid. Seems viable. If I explore deeper I'll start a threat on my findings and link back to this thread.
This thread is important. Years gone by and looking at where I am now, versus where I was when I posted here. The drive limit hasn't changed. UnRAID is still awesome. But my needs have changed. I'm happy to purchase more UnRAID licenses, but I don't want to manage multiple UnRaid servers. Three is enough.
Any ideas on what else to explore or consider?