ZnH2: Augmenting ZNS-based Storage System with Host-Managed Heterogeneous Zones

Zoned Namespace (ZNS) is an emerging interface that shows great promise for high-density and low-cost cloud environment deployments. Modern high-density SSDs, on the other hand, typically use a hybrid SLC/QLC architecture to mitigate the deficiencies of QLC. Unfortunately, simply integrating ZNS with the mainstream host-transparent hybrid architecture would lead to substantial performance and endurance overhead, defeating the purpose of this architecture in the first place.