Volley: Accelerating Write-Read Orders in Disaggregated Storage

Modern data centers deploy disaggregated storage systems (e.g., NVMe over Fabrics, NVMe-oF) for fine-grained resource elasticity and high resource utilization. A client-side writeback cache is used to absorb writes and buffer frequently accessed data, thereby eliminating unnecessary remote storage accesses and improving performance. Yet, a cache miss on the full cache triggers an evict-and-fetch operation which evicts the old entries before new data blocks are fetched. Existing systems perform the evict-and-fetch operation by sequentially executing write and read I/O operations, which reduces the concurrency and makes it challenging to fully utilize the fast network and storage devices.