Out of curiosity, how do windows filesystems for solutions like these compare to ZFS in terms of reliability and features ?
ZFS has been my only choice for NAS servers at home primarily due to it's data integrity features.
The combination of Storage Spaces and ReFS is pretty nice. Drives are added to storage pool and then block devices are allocated out of the pool. The blocks devices are thinly provisioned and expandable, so it's more flexible than it sounds. If you create a block device that has redundancy (either mirroring or RAIDZ-like parity), you get the data integrity like ZFS. I beleive the system also does periodic scrubbing.
One advantage of this setup is you can have multiple block devices of differing parity on top of the same pool. The pool is also more flexible than ZFS, allowing you to add drives of different sizes and later remove drives.
The main thing I miss from ZFS is the ability to create snapshots and do zfs send/receive for backups. Also not being able to read the source code is a bummer.
