High-performance Storage Systems Research Articles

A New Strategy to Fabricate Nanoporous Gold and Its Application in Photodetector.

Nanoporous gold (NPG) plays an important role in high-performance electronic devices, including sensors, electrocatalysis, and energy storage systems. However, the traditional fabricating methods of NPG, dealloying technique or electrochemical reduction technique, usually require complex experimental procedures and sophisticated equipment. In this work, we reported a unique and simple method to prepare the NPG through a low-temperature solution process. More importantly, the structure of the NPG-based electrode can be further controlled by using the post-treatment process, such as thermal treatment and plasma treatment. Additionally, we also demonstrate the application of the resulting NPG electrodes in flexible photodetectors, which performs a higher sensitivity than common planar photodetectors. We believe that our work opens a possibility for the nanoporous metal in future electronics that is flexible, large scale, with facile fabrication, and low cost.

The Fundamentals of NAND Flash Memory: Technology for tomorrow’s fourth industrial revolution

With the rise of the mobile-centric era, data-driven applications such as the Internet of Things, artificial intelligence, cloud computing, blockchain, and so on are ever increasing. As these applications create unprecedented amounts of data, the technologies used for collecting, processing, and storing them well are becoming more crucial. According to the research in <xref ref-type="bibr" rid="ref1">[1]</xref>, the amount of data we generate has a growth rate of 2.5 times per every four years, and the total amount of data will reach 175 ZB by 2025. Such a &#x201C;Big Bang&#x201D; of data means a tremendous demand on storage systems; it is evident that high-capacity and high-performance storage systems will play a key role. Therefore, along with this trend, NAND flash memory technology has continued to evolve to meet high demands. This article covers key technologies for high-density/high-performance NAND flash memory.

QBLKe: Host-side flash translation layer management for Open-Channel SSDs

Open-Channel SSD (OCSSD) shows great potential in high-performance storage systems. Existing applications or file systems rely on host-based Flash Translation Layer (FTL) to use OCSSDs. However, the existing solution cannot fully exploit the OCSSD performance under multi-thread workloads. On the read/write critical paths, we find three components (ring buffer, translation map, and DMA memory pool) that use global spinlocks to achieve atomicity. The spinlocks exhaust CPU time and thus hurt system scalability. Besides, as the number of OCSSD parallel units increases, the granularity of garbage collection (GC) of the existing solution also increases. This results in unnecessary page migrations during GC. In this article, we propose QBLKe as an OCSSD host-based FTL. QBLKe adopts three techniques to improve scalability and minimize software overhead: (1) per-CPU ring buffer, (2) lock-free translation map, and (3) per-CPU DMA pool. To further minimize GC page migrations and the impacts on I/O performance, QBLKe implements per-channel GC and a new scheme called score-based rate limiter. Experimental results show that QBLKe improves up to 78.9% write bandwidth compared with the existing solution. It also increases the peak read IOPS by 139.31% and the GC efficiency by 49.11%.

Design and Implementation of the first Generic Archive Storage Service for Research Data in Germany

Research data as the true valuable good in science must be saved and subsequently kept findable, accessible and reusable for reasons of proper scientific conduct for a time span of several years. However, managing long-term storage of research data is a burden for institutes and researchers. Because of the sheer size and the required retention time apt storage providers are hard to find.&#x0D; Aiming to solve this puzzle, the bwDataArchive project started development of a long-term research data archive that is reliable, cost effective and able store multiple petabytes of data. The hardware consists of data storage on magnetic tape, interfaced with disk caches and nodes for data movement and access. On the software side, the High Performance Storage System (HPSS) was chosen for its proven ability to reliably store huge amounts of data. However, the implementation of bwDataArchive is not dependant on HPSS. For authentication the bwDataArchive is integrated into the federated identity management for educational institutions in the State of Baden-Württemberg in Germany.&#x0D; The archive features data protection by means of a dual copy at two distinct locations on different tape technologies, data accessibility by common storage protocols, data retention assurance for more than ten years, data preservation with checksums, and data management capabilities supported by a flexible directory structure allowing sharing and publication. As of September 2019, the bwDataArchive holds over 9 PB and 90 million files and sees a constant increase in usage and users from many communities.

AutoBahn: a concurrency control framework for non-volatile file buffer

Storage systems in general and databases in particular usually balance between write durability and performance. It is not uncommon that write durability often relies on transaction systems that also offer a relaxed model of durability for performance. As hardware vendors provision more cores and faster storage devices, attaining fast data durability for concurrent file writes is demanding to high-performance storage systems in large-scale cluster systems. We approach the challenge by proposing a system that uses a small amount of fast persistent memory for buffering concurrent file writes while preserving data durability. The main technical issue in designing a durable file buffer is allowing concurrent file writes to store data in a shared and limited space of persistent memory without incurring lock or resource contention. This article addresses such issue and presents AutoBahn, a durable file buffer that expedites file I/O operations. To prove practicality and effectiveness, we implemented a prototype of AutoBahn in Linux-4.8.7 and ran several key-value systems—Redis, RocksDB, and WiredTiger—on AutoBahn. Evaluation results on a multicore server demonstrate that all the key-value systems achieved performance levels almost matching the non-durable counterpart. AutoBahn is a useful method that can efficiently deal with concurrent file I/O streams on multicores and fast storage devices.

Laser welding of laser-structured copper connectors for battery applications and power electronics

The electrification of the automobile industry leads to an increasing demand for high-performance energy storage systems. The more complex the battery pack, the more complex the electronic components will become. Very high currents have to be transported in a short time and very fast electrical switching processes have to be made possible. These requirements have an effect on the required quality of the electrical connection. Furthermore, a joining process is required that offers short cycle times and a high degree of automation. Laser micro welding with fibre lasers (1070 nm) meets the requirements placed on joining technology. Due to the high beam quality, very small spot diameters and thus very high intensities can be achieved. Copper materials of high purity are used to achieve the high conductivity of the electrical connection. This material, in turn, poses a great challenge to the welding process, since the reflectance for the beam sources mentioned is above 95%.This paper presents a way of significantly reducing the reflectance for copper connectors and thus making the joining process more efficient. For this purpose, the copper connectors are first pre-processed with an ultrashort pulse laser process, which significantly increases the surface area. In a second step, bead-on-plate welds are carried out on the structured surfaces and the absorption coefficient is determined during the welding process with the aid of a double integrating sphere assembly in comparison to a bare copper sample.

Mechanism, strategies, and characterizations of Li plating in solid state batteries

Commercial lithium-ion batteries have inherent safety problems due to the usage of non-aqueous electrolyte as the electrolytes. The development of solid state lithium metal batteries is expected to solve these problems while achieving higher energy density. However, the problem of lithium plating still exists. This article reviews the deposition behavior of lithium metal anodes in solid-state batteries, and provides suggestions for high-energy-density and high-safety solid-state lithium batteries. This paper systematically summarizes the mechanism of Li deposition in polymers and inorganic solid state electrolytes, and discusses the strategies of controlling lithium deposition and preventing lithium dendrites and the characterization of Li metal anodes. In solid-state batteries, poor solid-solid contact between the electrolyte and the anode, defects, grain boundaries, cracks, pores, enhanced electric and ionic fields near the tip, and high electronic conductivity of the solid state electrolyte can all lead to lithium deposition, which may evolve into lithium dendrites. There are several strategies to control lithium deposition: 1). Use functional materials and structure design to induce uniform deposition of lithium, such as improving the solid state electrolyte/anode interfacial contact, using lithiophilic coatings or sites, and designing three-dimensional structure electrodes and solid state electrolytes. 2). Suppress the generation of lithium dendrites, such as limiting the free movement of anions in solid state electrolytes (especially polymer solid electrolytes), to reduce local space charge which induces lithium dendrites. In addition, optimizing the solid electrolyte synthesis process to reduce lithium dendrites caused by defects is also an important method. 3). Strategies for dendrites already formed are essential for safety concern. The dendritic deposition is one of the intrinsic properties of lithium. Thus, there is no guarantee that there will be no lithium dendrites, especially at high current density. Once lithium dendrites are formed, countermeasures are required. For example, improving the mechanical strength of solid state electrolytes, and using self-healing materials, structures, and cycling conditions are proposed to avoid safety hazards caused by lithium dendrites piercing. This article focuses on the control of lithium deposition. Suppressing lithium dendrites only solves a little problem of the application of lithium metal anodes. In the future, in order to use lithium metal as a negative electrode in practical all-solid-state batteries, many challenges need to be overcome, such as irreversible side reactions between lithium and other materials, safety and volume change of composite lithium anodes. In addition, in order to allow the laboratory's research results to be quickly transformed into applications, it is also necessary to establish battery design, assembly, and test standards that are in agreement with practical requirements. In short, all-solid-state lithium batteries still have a long way to go, but they have great potential for safe, high-performance, and low-cost energy storage systems in the future.

High-performance Energy Storage System Using Low-cost Sensors for a Photovoltaic and Battery Hybrid System

High-performance Energy Storage System Using Low-cost Sensors for a Photovoltaic and Battery Hybrid System

ZoneTier

Integrating solid-state drives (SSDs) and host-aware shingled magnetic recording (HA-SMR) drives can potentially build a cost-effective high-performance storage system. However, existing SSD tiering and caching designs in such a hybrid system are not fully matched with the intrinsic properties of HA-SMR drives due to their lacking consideration of how to handle non-sequential writes (NSWs). We propose ZoneTier, a zone-based storage tiering and caching co-design, to effectively control all the NSWs by leveraging the host-aware property of HA-SMR drives. ZoneTier exploits real-time data layout of SMR zones to optimize zone placement, reshapes NSWs generated from zone demotions to SMR preferred sequential writes, and transforms the inevitable NSWs to cleaning-friendly write traffics for SMR zones. ZoneTier can be easily extended to match host-managed SMR drives using proactive cleaning policy. We implemented a prototype of ZoneTier with user space data management algorithms and real SSD and HA-SMR drives, which are manipulated by the functions provided by libzbc and libaio. Our experiments show that ZoneTier can reduce zone relocation overhead by 29.41% on average, shorten performance recovery time of HA-SMR drives from cleaning by up to 33.37%, and improve performance by up to 32.31% than existing hybrid storage designs.

A high-performance pseudocapacitive electrode material for supercapacitors based on the unique NiMoO4/NiO nanoflowers

Currently, although some progress has already been achieved, the complex and high-cost synthetic route, and low electrochemical properties of supercapacitor still restrict its practical application. Here, NiMoO4/NiO nanoflowers material with a high specific surface area grown on a nickel foam conductive substrate is successfully synthesized via a facile and efficient method, which exhibits an excellent capacitance of 10.3 F cm−2 (1982.3 F g−1), a good rate capability, and a remarkable cycling stability (capacity remain 98.6% after 3000 cycles). In addition, a novel asymmetric supercapacitor with excellent energy density is also fabricated via the NiMoO4/NiO nanoflowers as the positive electrode and a piece of active carbon as the negative electrode in 3 M KOH electrolyte. The optimized asymmetric device operating at 1.7 V also offers a high energy density and an outstanding long-term cycling stability. These impressive results suggest that such NiMoO4/NiO nanoflowers can pave the way for designing and developing next-generation high-performance storage systems.

ECI-Cache

In recent years, high interest in using Virtual Machines (VMs) in data centers and cloud computing has significantly increased the demand for high-performance data storage systems. A straightforward approach to providing a high-performance storage system is using Solid-State Drives (SSDs). Inclusion of SSDs in storage systems, however, imposes significantly higher cost compared to Hard Disk Drives (HDDs). Recent studies suggest using SSDs as a caching layer for HDD-based storage subsystems in virtualized platforms. Such studies neglect to address the endurance and cost of SSDs, which can significantly affect the efficiency of I/O caching. Moreover, previous studies only configure the cache size to provide the required performance level for each VM, while neglecting other important parameters such as cache write policy and request type, which can adversely affect both performance-per-cost and endurance. In this paper, we propose a new high-Endurance and Cost-efficient I/O caching (ECI-Cache) scheme for virtualized platforms in large-scale data centers, which improves both performance-per-cost and endurance of the SSD cache. ECI-Cache dynamically assigns 1) an efficient cache size for each VM, to maximize the overall performance of the running VMs and 2) an effective write policy for each VM, to enhance the endurance and performance-per-cost of the storage subsystem.

ECI-Cache

In recent years, high interest in using Virtual Machines (VMs) in data centers and Cloud computing has significantly increased the demand for high-performance data storage systems. A straightforward approach to provide a high performance storage system is using Solid-State Drives (SSDs). Inclusion of SSDs in storage systems, however, imposes significantly higher cost compared to Hard Disk Drives (HDDs). Recent studies suggest using SSDs as a caching layer for HDD-based storage subsystems in virtualization platforms. Such studies neglect to address the endurance and cost of SSDs, which can significantly affect the efficiency of I/O caching. Moreover, previous studies only configure the cache size to provide the required performance level for each VM, while neglecting other important parameters such as cache write policy and request type, which can adversely affect both performance-per-cost and endurance. In this paper, we present a new high-Endurance and Cost-efficient I/O Caching (ECI-Cache) scheme for virtualized platforms, which can significantly improve both the performance-per-cost and endurance of storage subsystems as opposed to previously proposed I/O caching schemes. Unlike traditional I/O caching schemes which allocate cache size only based on reuse distance of accesses, we propose a new metric, Useful Reuse Distance (URD), which considers the request type in reuse distance calculation, resulting in improved performance-per-cost and endurance for the SSD cache. Via online characterization of workloads and using URD, ECI-Cache partitions the SSD cache across VMs and is able to dynamically adjust the cache size and write policy for each VM. To evaluate the proposed scheme, we have implemented ECI-Cache in an open source hypervisor, QEMU (version 2.8.0), on a server running the CentOS 7 operating system (kernel version 3.10.0-327). Experimental results show that our proposed scheme improves the performance, performance-per-cost, and endurance of the SSD cache by 17%, 30% and 65%, respectively, compared to the state-of-the-art dynamic cache partitioning scheme.

ATHLET simulation code: Model validation of a thermal high-performance storage system

ATHLET simulation code: Model validation of a thermal high-performance storage system

Model Development and Dynamic Simulation of a Thermal High-Performance Storage System with the Simulation Code ATHLET to Increase the Flexibility of T

Model Development and Dynamic Simulation of a Thermal High-Performance Storage System with the Simulation Code ATHLET to Increase the Flexibility of T

Adaptive hybrid storage systems leveraging SSDs and HDDs in HPC cloud environments

Cloud computing should inherently support various types of data-intensive workloads with different storage access patterns. This makes a high-performance storage system in the Cloud an important component. Emerging flash device technologies such as solid state drives (SSDs) are a viable choice for building high performance computing (HPC) cloud storage systems to address more fine-grained data access patterns. However, the bit-per-dollar SSD price is still higher than the prices of HDDs. This study proposes an optimized progressive file layout (PFL) method to leverage the advantages of SSDs in a parallel file system such as Lustre so that small file I/O performance can be significantly improved. A PFL can dynamically adjust chunk sizes and stripe patterns according to various I/O traffics. Extensive experimental results show that this approach (i.e. building a hybrid storage system based on a combination of SSDs and HDDs) can actually achieve balanced throughput over mixed I/O workloads consisting of large and small file access patterns.

Information infrastructure development in NRU «MPEI»

The article describes the work on support and development of information infrastructure NRU «MPEI». Information infrastructure have different approaches to the defi nition. The authors defi ne the information infrastructure as a set of basic information services, computing, storage and data transmission systems that provide user access to information resources. New conditions dictate new approaches to building the education system in general and the educational process in each educational institution. NRU «MPEI» working to create a modern information infrastructure, including automated control systems, information resources and services, modular systems disciplines. This article describes the requirements for a modern information infrastructure of the NRU «MPEI», that provides students and teachers with the necessary services. Information infrastructure includes a set of software and hardware to ensure interaction between the participants of the educational process. All services and NRU «MPEI» system included in the unifi ed information educational environment (UIEE). Architecture UIEE NRU «MPEI» is displayed in the article. UIEE NRU «MPEI» is deployed on the basis of information network NRU «MPEI» and enables a comprehensive optimization of university management in various areas. Information and Computing Center supporting information and computer network NRU «MPEI», bought more than 4800 licenses in 43 different license versions of the software manufacturers. The server segment information network NRU «MPEI» contains a complex infrastructure and application servers for processing and storing information. The segment there are 20 high-performance server and storage system capacity of over 30 TB. In the server segment deployed complex systems to meet the needs in the various fi elds of activity NRU «MPEI», and the educational system to support the economic , scientifi c and human complex. Currently, ICC also pays great attention to the development of educational and innovation center, the initiative is aimed at improving the qualifi cations of teaching staff and training of students. For example, SAP technology are in fact the standard of corporate information systems for large enterprises, it is about 49.9% of the worldmarket. Therefore, every year, since 2008, the SAP Training Center - MPEI produces 40-45 graduates to work in energy companies and other industries. The preparation of an engineer is a challenge and a decision it is not possible without the widespread introduction of information and communication technologies in all spheres of activity of the university: teaching, research , management of the various spheres of activity . According to the authors , the use of modern information infrastructure for Engineering Education will allow to solve this problem effectively.

Superset: a non-uniform replica placement strategy towards perfect load balance and fine-grained power proportionality

Load balance and power proportionality are both important aspects in constructing high-performance and cost-effective distributed storage systems. However, traditional replica placement strategies which provide load balance usually produce scattered replica layouts, thus disabling power proportionality, while recent strategies that enable power proportionality are typically based on uniform replication, thus compromising the ability of load balance. In this article, we introduce Superset (an organized non-uniform replica placement strategy) which takes both load balance and power proportionality into consideration. The main idea is to partition the whole system into several uniform replication based subsystems with the accommodated file subsets satisfying the `superset' condition. We proved Superset to be theoretically effective, and conducted a series of simulations with real-world distributions of data popularity. Our results show that, compared to state of the art solutions, Superset consumes less energy to fulfill the same performance requirement while offers higher performance subject to the same energy consumption constraint.

Mojim

Next-generation non-volatile memories (NVMs) promise DRAM-like performance, persistence, and high density. They can attach directly to processors to form non-volatile main memory (NVMM) and offer the opportunity to build very low-latency storage systems. These high-performance storage systems would be especially useful in large-scale data center environments where reliability and availability are critical. However, providing reliability and availability to NVMM is challenging, since the latency of data replication can overwhelm the low latency that NVMM should provide. We propose Mojim, a system that provides the reliability and availability that large-scale storage systems require, while preserving the performance of NVMM. Mojim achieves these goals by using a two-tier architecture in which the primary tier contains a mirrored pair of nodes and the secondary tier contains one or more secondary backup nodes with weakly consistent copies of data. Mojim uses highly-optimized replication protocols, software, and networking stacks to minimize replication costs and expose as much of NVMM?s performance as possible. We evaluate Mojim using raw DRAM as a proxy for NVMM and using an industrial NVMM emulation system. We find that Mojim provides replicated NVMM with similar or even better performance than un-replicated NVMM (reducing latency by 27% to 63% and delivering between 0.4 to 2.7X the throughput). We demonstrate that replacing MongoDB's built-in replication system with Mojim improves MongoDB's performance by 3.4 to 4X.

Mojim

Next-generation non-volatile memories (NVMs) promise DRAM-like performance, persistence, and high density. They can attach directly to processors to form non-volatile main memory (NVMM) and offer the opportunity to build very low-latency storage systems. These high-performance storage systems would be especially useful in large-scale data center environments where reliability and availability are critical. However, providing reliability and availability to NVMM is challenging, since the latency of data replication can overwhelm the low latency that NVMM should provide. We propose Mojim, a system that provides the reliability and availability that large-scale storage systems require, while preserving the performance of NVMM. Mojim achieves these goals by using a two-tier architecture in which the primary tier contains a mirrored pair of nodes and the secondary tier contains one or more secondary backup nodes with weakly consistent copies of data. Mojim uses highly-optimized replication protocols, software, and networking stacks to minimize replication costs and expose as much of NVMM?s performance as possible. We evaluate Mojim using raw DRAM as a proxy for NVMM and using an industrial NVMM emulation system. We find that Mojim provides replicated NVMM with similar or even better performance than un-replicated NVMM (reducing latency by 27% to 63% and delivering between 0.4 to 2.7X the throughput). We demonstrate that replacing MongoDB's built-in replication system with Mojim improves MongoDB's performance by 3.4 to 4X.

IOPro: a parallel I/O profiling and visualization framework for high-performance storage systems

Efficient execution of large-scale scientific applications requires high-performance computing systems designed to meet the I/O requirements. To achieve high-performance, such data-intensive parallel applications use a multi-layer layer I/O software stack, which consists of high-level I/O libraries such as PnetCDF and HDF5, the MPI library, and parallel file systems. To design efficient parallel scientific applications, understanding the complicated flow of I/O operations and the involved interactions among the libraries is quintessential. Such comprehension helps identify I/O bottlenecks and thus exploits the potential performance in different layers of the storage hierarchy. To profile the performance of individual components in the I/O stack and to understand complex interactions among them, we have implemented a GUI-based integrated profiling and analysis framework, IOPro. IOPro automatically generates an instrumented I/O stack, runs applications on it, and visualizes detailed statistics based on the user-specified metrics of interest. We present experimental results from two different real-life applications and show how our framework can be used in practice. By generating an end-to-end trace of the whole I/O stack and pinpointing I/O interference, IOPro aids in understanding I/O behavior and improving the I/O performance significantly.