Don’t Stack Your Log On My Log

摘要: Log-structured applications and file systems have been used to achieve high write throughput by sequentializing writes. Flash-based storage systems, due flash memory’s out-of-place update characteristic, also relied on log-structured approaches. Our work investigates the impacts performance endurance in when multiple layers of are layered top a device. We show that log affects sequentiality increases pressure devices through randomization workloads, unaligned segment sizes, uncoordinated multi-log garbage collection. All these effects can combine negate intended positive using log. In this paper we characterize interactions between levels independent logs, identify issues must be considered, describe design choices mitigate negative behaviors configurations.