draid uses the raidz allocator. Thus it is subject to the same allocation
efficiencies as raidz and
described here
https://www.delphix.com/blog/delphix-engineering/zfs-raidz-stripe-width-or-how-i-learned-stop-worrying-and-love-raidz
The short answer is: avoid using raidz with small recordsize or
vo
A little more background...
The choice of a pool with 4x raid2:3d has more to do with a sweet spot for
our use case and budget.
I have twenty or so small NAS appliances, currently each with 5x 3.8TB
enterprise SATA SSDs and an Optane log. These each serve a handful of
datasets via NFSv3 to a pool