I'm looking for a minimal ZFS setup to achieve self-healing on a single device. Since I back up my data, drive failures are no concern, but bit-rot is. So far, the only suggestions I've been able dredge up pointed to the copies=2
option, but that cuts the usable capacity by 50%.
My question: What are the drawbacks (other than performance) to split the device into 8 partitions and joining them into a 7+1 RAID-Z1 array? That would mean a 12.5% reduction in usable space. While I'm at it, why not go 19+1 or 99+1 (or whatever the partition table allows)?
Best Answer
From the ZFS Best Practices Guide:
To sum it up, it is much much slower and more difficult to correctly handle, replace and grow.
Additionally, you still have to care about your pool layout. Your RAIDZ1 setup would still suffer from the RAID5 write hole problem while replacing the slice, and it will still suffer if you choose non-optimal amounts of slices for your RAIDZ level (also from the recommendations in the guide):