DINOMO: An Elastic, Scalable, High-Performance Key-Value Store for Disaggregated Persistent Memory (Extended Version)

We present Dinomo, a novel key-value store for disaggregated persistent memory (DPM). Dinomo is the first key-value store for DPM that simultaneously achieves high common-case performance, scalability, and lightweight online reconfiguration. We observe that previously proposed key-value stores for DPM had architectural limitations that prevent them from achieving all three goals simultaneously. Dinomo uses a novel combination of techniques such as ownership partitioning, disaggregated adaptive caching, selective replication, and lock-free and log-free indexing to achieve these goals. Compared to a state-of-the-art DPM key-value store, Dinomo achieves at least 3.8x better throughput on various workloads at scale and higher scalability, while providing fast reconfiguration.Comment: This is an extended version of the full paper to appear in PVLDB 15.13 (VLDB 2023

Synthesizing Representative I/O Workloads Using Iterative Distillation

Storage systems designers are still searching for better methods of obtaining representative I/O workloads to drive studies of I/O systems. Traces of production workloads are very accurate, but inflexible and difficult to obtain. (Privacy and performance concerns discourage most system administrators from collecting such traces and making them available to the public.) The use of synthetic workloads addresses these limitations; however, synthetic workloads are accurate only if they share certain key properties with the production workload on which they are based (e.g., mean request size, read percentage). Unfortunately, we do not know which properties are "key" for a given workload and storage system. We have developed a tool, the Distiller, that automatically identifies the key properties (more formally called attribute-values) of the workload. These attribute-values can then be used to generate a synthetic workload representative of the production workload. This paper presents the design and evaluation of the Distiller. We demonstrate how the Distiller finds representative synthetic workloads for simple artificial workloads and three production workload traces

The woods around the ivory tower: A systematic review examining the value and relevance of school forests in the United States

Throughout the United States, many institutions of higher education own forested tracts, often called school forests, which they use for teaching, research, and demonstration purposes. These school forests provide a range of benefits to the communities in which they are located. However, because administration is often decoupled from research and teaching, those benefits might not always be evident to the individuals who make decisions about the management and use of school forests, which may undervalue their services and put these areas at risk for sale, development, or over-harvesting to generate revenue. To understand what messages are being conveyed about the value and relevance of school forests, we conducted a systematic literature review and qualitatively coded the resulting literature content using an ecosystem services framework. While school forests provide many important benefits to academic and local communities, we found that most of the existing literature omits discussions about cultural ecosystem services that people may receive from school forests. We discuss the implications of this omission and make recommendations for addressing it

WiscSort: External Sorting For Byte-Addressable Storage

We present WiscSort, a new approach to high-performance concurrent sorting for existing and future byte-addressable storage (BAS) devices. WiscSort carefully reduces writes, exploits random reads by splitting keys and values during sorting, and performs interference-aware scheduling with thread pool sizing to avoid I/O bandwidth degradation. We introduce the BRAID model which encompasses the unique characteristics of BAS devices. Many state-of-the-art sorting systems do not comply with the BRAID model and deliver sub-optimal performance, whereas WiscSort demonstrates the effectiveness of complying with BRAID. We show that WiscSort is 2-7x faster than competing approaches on a standard sort benchmark. We evaluate the effectiveness of key-value separation on different key-value sizes and compare our concurrency optimizations with various other concurrency models. Finally, we emulate generic BAS devices and show how our techniques perform well with various combinations of hardware properties

A Framework for Evaluating Storage System Dependability

Abstract—Designing storage systems to provide business continuity in the face of failures requires the use of various data protection techniques, such as backup, remote mirroring, point-in-time copies and vaulting, often in concert. Predicting the dependability provided by such compositions of techniques is difficult, yet necessary for dependable system design. We present a framework for evaluating the dependability of data storage systems, including both individual data protection techniques and their compositions. Our models estimate storage system recovery time, data loss, normal mode system utilization and operational costs under a variety of failure scenarios. We demonstrate the effectiveness of these modeling techniques through a case study using real-world storage system designs and workloads.