I have a mac fileserver with multiple drives that I'd like to combine into a single pool (such that the filesystems appear to be combined together) and then have accessible as a network share, preferably using SMB.
The sort of drive pooling I'm after is similar to what's possible with filesystems like UnionFS, mergerfs, or mhddfs in Linux, or what can be accomplished specifically as a network share with something like Greyhole.
Edit: I should note that I need the drives to remain accessible as separate volumes so that I can protect their data using snapraid.
I've already found this question from earlier: Pool Multiple Hard Drives in ONE network Share
...but its answers are over five years old now and don't work in modern versions of macOS. In particular
mhddfs is no longer maintained and isn't usable in macOS any longer. Unfortunately none of these other linux pooling filesystems are available for macOS.
Is there any way to accomplish this?