Krishnamurthy, ArvindMin, Jaehong2025-08-012025-08-012025Min_washington_0250E_27977.pdfhttps://hdl.handle.net/1773/53514Thesis (Ph.D.)--University of Washington, 2025Disaggregated storage architectures have become a foundational element in modern datacenter design, enabling independent scaling of compute and storage resources. However, supporting multi-tenant workloads on shared flash-based storage devices remains challenging due to interference, limited hardware isolation, and host-centric software bottlenecks. This dissertation explores system and interface designs that leverage hardware innovations—specifically, SmartNICs and NVMe SSDs—to improve performance, fairness, and adaptability in disaggregated storage systems. The first part introduces Gimbal, a software storage switch that enables multi-tenant-aware scheduling and congestion control on SmartNIC-based storage nodes. Gimbal employs write cost estimation, credit-based flow control, and hierarchical I/O scheduling to isolate tenants and maintain throughput fairness under constrained compute budgets. We then present eZNS, an elastic Zoned Namespace abstraction that enables dynamic resource allocation for ZNS SSDs. eZNS decouples rigid namespace boundaries and allows flexible sharing of zones through global and local overdrive policies. Coordinated I/O planning and proactive space management improve utilization and write efficiency while preserving predictable performance. Lastly, we propose the Interposable Transport Protocol (ITP), a transport-layer abstraction for SmartNIC-based disaggregated storage. ITP enables in-network request redirection, replication, and remote memory access by treating SmartNICs as protocol-aware dataplane processors. The prototype demonstrates that forwarding and RMA operations can complete within single-digit microseconds using ARM cores, achieving near-RDMA performance without dedicated hardware support. Collectively, these contributions show that co-designing software abstractions with emerging hardware enables disaggregated storage systems to achieve high performance, adaptability, and strong multi-tenant isolation. The proposed designs lay a foundation for scalable, composable storage infrastructure in modern cloud environments.application/pdfen-USnoneComputer scienceComputer science and engineeringThesis