基于SCSI的故障注入工具设计与实现

研究海量存储系统的可用性评测,设计一种基于小型计算机系统接口(SCSI)协议的故障注入工具。该工具在SCSI协议中间层截获SCSI上层命令,修改命令后,能够实现多种暂态和永久故障的注入,有效地模拟存储系统可能遇到的各种故障。根据目标系统特点确定故障模型和注入参数,注入结束后,进行注入结果回收和离线数据分析。实验测试结果验证了该故障注入工具的有效性。     

网络iSCSI-RAID存储系统性能研究

由于iSCSI协议将TCP/IP协议和SCSI很好地结合起来,所以基于iSCSI协议建立网络存储系统具有开放性好、易于扩展、建设成本低等特点。利用iSCSI软件实现方式,设计实现了网络iSCSI-RAID存储系统,并通过实验分析了RAID布局、存储结点数、网络带宽和条纹单元大小等性能影响因素对系统性能的影响,为改进网络iSCSI-RAID存储系统性能提供了依据。     

使用批量处理方法提高iSCSI存储系统性能的策略研究

iSCSI存储系统在IP网络上传输SCSI协议,但是在网络上大量的SCSI命令、状态以及小数据的传输严重影响了网络存储系统的性能.传统的批量处理方法将多个小的命令请求合并为一个大的请求,然而参数K的设定基于经验,缺少定量分析.通过排队理论建立SCSI命令批量处理的数学模型,然后在iSCSI存储协议结构中设计K-batch模块,最后应用网络仿真软件ns-2建立仿真场景对存储系统进行测试.随着命令到达率λ的变化,批量处理参数K作相应的实时调整.实验结果显示,该批量处理策略可明显降低命令的平均响应时间,提高iSCSI存储系统性能.     

IP存储技术研究

IP存储是一种新的网络存储技术，它将SCSI协议映射到TCP／IP协议上，使得SCSI的命令、数据和状态可以在传统的IP网上传输，支持数据块形式的I／O访问和共享存储。本文主要研究iSCSI存储系统结构、iSCSI协议和iSCSI存储的关键技术。     

一种SCSI目标器设计与评估

SCSI目标器是磁盘阵列控制器软件中的关键组成部分之一;设计并实现了一种SCSI目标器,详细描述了SCSI目标器的功能及其内部体系结构,阐述了目标器对读写请求的不同处理流程;该SCSI目标器是可配置的,它既能够辅助磁盘阵列控制器软件系统开发,也能够胜任磁盘阵列控制器SCSI目标器的功能;为了验证该SCSI目标器的性能,采用相关评测工具对其有负载和无负载两种情况的读写性能进行了评测,测试结果表明该SCSI目标器的实际性能达到了预期的设计目标。     

SAS通道技术

在校园数字化的建设过程中,数据资料快速膨胀。为了满足数据存储的需求,更多的学校开始把注意力转向大型的存储系统。顾名思义,存储系统需要有大量的硬盘装载能力,承担海量数据存储的要求,而存储系统的架构设计则直接影响到系统的性能、最大磁盘数等核心指标。本文重点介绍了SAS（Serial Attached SCSI串行SCSI）通道技术的技术细节,如技术架构、各类端口命名和含义、宽端口技术等,并且和原有的存储系统通道技术,如FC协议,进行了比较。并且认为,SAS作为磁盘通道技术,在接口带宽、工作性能、可扩展性、组网应用、可靠性等方面,有着突出的优势,尤其适合应用于企业级系统。     

一种适合海量存储的安全网络存储系统

本文基于NASD融合SAN为一种适合海量存储的安全网络存储系统SNS,满足高带宽、大规模、易扩展的海量存储需要.给出了存储系统的网络协议,由可信接入认证协议和安全信道协议两部分组成.协议在两轮交互中就完成了用户与服务器间的身份认证和长期密钥确认,并在首轮交互中完成对用户端平台的身份认证和完整性校验,提高了协议执行的效率...     

基于ASPI和SCSI的高速视频存储系统

针对目前靶场光学测量设备大量使用高帧频、高像素值的数字CCD相机,设计了一种基于SCSI接口的高速数字视频存储系统;硬件平台采用普通PC机,软件使用ASPI指令直接在数字视频采集卡和SCSI适配器之间通过64 bit PCI-X总线实现数据传输,避开了操作系统和文件系统的速率瓶颈;在实际应用中可实现带宽为100MB/s,总容量为200GB以上的数据存储,取得了预期效果;实现了低成本平台和高效率存储的统一.     

SAS技术的设计开发及应用

SAS(Serial Attached SCSI)即串行SCSI(Small Computer System Interface)技术,是一种磁盘连接技术。它综合了并行SCSI和串行连接技术的优势,以串行通讯协议为协议基础架构,采用SCSI-3扩展指令集,并兼容SATA设备,是多层次的存储设备连接协议。     

云存储性能评测研究

大数据时代的到来,使得对云存储产生了强烈的需求。云存储性能评测一直是云存储系统研究的热点与难点。通过分析典型云存储平台数据访问的过程,建立云存储数据读写的模型,利用网络分析工具iptools获得云存储系统在处理用户访问请求的各个阶段的时间开销,从中排除网络干扰,反映真正云存储系统数据读写性能。实验结果表明,这种云存储系统数据读写模型是科学合理的,按照模型设计的云存储系统性能评测方法能够有效排除网络干扰,获取反映云存储系统真正读写性能的数据。     

Distributed fault detection in industrial system based on sensor wireless network

In metal cutting processes, an effective monitoring system, based on a suitably developed scheme or set of algorithms can maintain machine tools in good condition and delay the occurrence of tool wear. In this paper, an approach is developed for fault detection based on a distributed system. Firstly, identifying of sensor instrumentation system is responsible for the signal processing and the system fault information. Secondly, the sensor wireless networks are used to transmit the data (lower layer) to or receive the commands from the computer center (top layer). Thirdly, the computer center at the top layer will monitor the overall system and generate the alarm signals or the commands when the faults occur.     

基于iSCSI协议的IP网络安全存储结构设计探讨

iSCSI协议定义了在IP网络上传输SCSI命令、数据和状态的规则和方法,使得基于iSCSI协议的安全存储结构比传统的基于FC协议的存储在多方面都有明显的优势。设计新的基于iSCSI协议的安全存储结构时,要在能够发挥该网络存储优势的同时兼顾保护IP网络的安全,以便新系统能够应用于需要构建基于iSCSI协议的安全存储结构并且对安全性较高的企业单位。研究采用外挂式存储虚拟化结构,实现IP网络安全存储要求。     

Performance of a Scalable Multimedia Server with Shared-Storage Clusters

The existing SCSI parallel bus has been widely used in various multimedia applications. However, due to the unfair bus accesses the SCSI bus may not be able to fully utilize the potential aggregate throughput of disks. The number of disks that can be attached to the SCSI bus is limited, and link level fault tolerance is not provided. The serial storage interfaces such as Serial Storage Architecture (SSA) provide high data bandwidth, fair accesses, long transmission distance between adjacent devices (disks or hosts) and link level fault tolerance. The fairness algorithm of SSA ensures a fraction of data bandwidth to be allocated to each device. In this paper we would like to know whether SSA is a better alternative in supporting continuous media than SCSI. The scalability of a multimedia server is very important since the storage requirement may grow incrementally as more contents are created and stored. SSA in a shared-storage cluster environment also supports concurrent accesses by different hosts as long as their access paths are not overlapped. This feature is called spatial reuse. Therefore, the effective bandwidth over an SSA can be higher than the raw data bandwidth and the spatial reuse feature is critical to the scalability of a multimedia server. This feature is also included in FC-AL3 with a new mode called Multiple Circuit Mode (MCM). Using MCM, all devices can transfer data simultaneously without collision. In this paper we have investigated the scalability of shared-stroage clusters over an SSA environment.     

测试海量存储系统可用性的故障注入法

阐述了针对海量存储系统的可用性测试方法,采用基于故障注入的方法测试系统的恢复时间,给出了故障对系统可用性的影响评价,设计了模拟系统正常运行的负载设置方法、手动注入故障和模拟SCSI磁盘故障的方法。     

IBM xSerier345 SCSI硬盘磁盘阵列的实现

本文简要介绍了磁盘陈列技术原理和实践运用价值，并详细介绍如何在IBM xSerier345 SCSI硬盘上实现磁盘陈列的过程和方-击。说明利用RAID技术能提高磁盘存取速度、提高系统的客错能力。对那些网络管理员或系统维护员在存储设备的建设和维护过程中有很好的实践参考价值。     

Two Emerging Serial Storage Interfaces for Supporting Digital Libraries: Serial Storage Architecture (SSA) and Fiber Channel-Arbitrated Loop (FC-AL)

Digital libraries require not only high storage space capacity but also high performance storage systems which provide the fast accesses to the data. These requirements can not be efficiently supported with the traditional SCSI interfaces. Several serial storage interfaces have been proposed for constructing storage systems with high transfer bandwidth, large storage capacity, and fault tolerance feature. Among them, Serial Storage Architecture (SSA) and Fibre Channel-Arbitrated Loop (FC-AL) are considered as the next generation storage interfaces with broad industry support. Both technologies support simple cabling, long transmission distance, high data bandwidth, large capacity, fault tolerance, and fair sharing of link bandwidth. In this paper, a tutorial and a comparison of these two technologies are presented. The tutorial examines their interface specifications, transport protocols, fairness algorithms, and capabilities of fault tolerance. The comparison focuses on their protocol overhead, flow control, fairness algorithms, and fault tolerance. The paper also summarizes the recently proposed Aaron Proposal which incorporates features from both SSA and FC-AL and targets at merging these two technologies.     

Have storage area networks come of age?

Organizations are processing and storing an exploding volume of information. Because of this, they are looking for new ways to access their data more quickly and reliably across their networks. This has led organizations to begin using storage area networks (SANs) based on fibre channel technology. SANs link storage devices (such as disks, disk arrays, and tape drives) to create a pool of storage that users can access directly. In essence, SANs uncouple storage devices from the LAN and put them on their own network. This approach relieves bandwidth congestion on the LAN and permits much faster data access than today's LAN-based storage streams. SANs also permit better storage management and more fault tolerance. SANs have traditionally used Small Computer Systems Interface (SCSI) technology, but now fibre channel technology is allowing SANs to transmit data at higher speeds over greater distances, which should accelerate the adoption of the storage networks. Fibre channel is also more scalable than SCSI. Fibre-channel-based SAN technology has so many advantages that it will become increasingly popular, particularly as researchers correct its problems and develop ways for it to transmit data over even longer distances     

Data-based Fault Tolerant Control for Affine Nonlinear Systems Through Particle Swarm Optimized Neural Networks

In this paper, a data-based fault tolerant control (FTC) scheme is investigated for unknown continuous-time (CT) affine nonlinear systems with actuator faults. First, a neural network (NN) identifier based on particle swarm optimization (PSO) is constructed to model the unknown system dynamics. By utilizing the estimated system states, the particle swarm optimized critic neural network (PSOCNN) is employed to solve the Hamilton-Jacobi-Bellman equation (HJBE) more efficiently. Then, a data-based FTC scheme, which consists of the NN identifier and the fault compensator, is proposed to achieve actuator fault tolerance. The stability of the closed-loop system under actuator faults is guaranteed by the Lyapunov stability theorem. Finally, simulations are provided to demonstrate the effectiveness of the developed method.