Abstract: Zoned namespaces solid-state drive (ZNS SSD) mitigate the performance overhead of the conventional “block interface tax,” opening new opportunities for high-performance storage system design. At the same time, ZNS SSDs fundamentally reshape the storage model by exposing zones to the host, enforcing sequential writes within each zone, and offloading flash-management functions—such as garbage collection and address mapping—from the device to host software. These shifts introduce significant challenges for ZNS-based systems. This survey distills three key challenges: 1) write amplification induced by host-managed placement and reclamation, where co-locating mixed-lifetime data within zones increases GC copying, compaction-GC mismatch leads to redundant data migration, and inefficient zone-reset policies cause unnecessary rewrites; 2) limited parallelism under fixed zone/resource mapping and sequential-write constraints, further exacerbated by intra- and inter-zone contention; and 3) elevated consistency and reliability overheads arising from wear imbalance, crash-recovery metadata costs, and parity maintenance in multi-device settings. For each challenge, we organize state-of-the-art optimization techniques, summarize recent advances, and highlight representative studies. We also review widely used simulators/emulators and auxiliary tools that support ZNS prototyping, debugging, and performance tuning. Finally, we discuss promising research directions, including cross-layer hardware-software co-design, multi-level heterogeneous integration, systematic software-stack refinement, and holistic, system-wide optimization.