Unix系统SCSI冗余路径驱动程序的设计和实现

在主机和存储系统之间连接多条SCSI路径，在路径发生故障时RDP驱动程序将I／O切换到其他路径，以增加系统的可用性。通过将I／O负载均衡分布在各SCSI路径，能增加系统带宽。讨论了在Unix系统中RDP设备驱动程序的设计原理和实现。     

一个Linux多路径磁盘过滤驱动程序

研究Linux系统中多路径磁盘过滤驱动程序的设计和实现。驱动程序将物理磁盘的多路径封装为一个虚拟没备。虚拟设备的I／O请求转发到磁盘设备上执行，由路径选择算法将主机的负载均衡地分配到各路径上。当路径发生故障时由驱动程序将失败的I／O请求切换到其它路径，屏蔽了路径故障。驱动程序利用多路径改善了主机的I／O性能，提高了系统的可用性。     

存储区域网络中路径容错及负载均衡的研究

为利用存储区域网络的冗余路径,在主机上加入驱动程序对逻辑单元（LUN）的输入,输出请求进行截获。在故障路径上的I／O请求失败后。由驱动程序在正常路径上重新执行。路径失败时I／O请求直接发送给HBA驱动程序,避免了磁盘驱动程序中的无效重试过程,缩短了故障切换时间。I／O请求被分配到多条路径上,提高了主机的吞吐能力,缩短了I／O平均响应时间。     

基于ALUA的多路径存储系统

随着网络存储技术的不断深入发展与广泛应用,存储多路径技术成为信息系统容灾与故障恢复方案中的核心技术之一.在现有存储多路径技术的基础上,提出了一种基于ALUA的多路径存储子系统总体框架,并重点在逻辑卷控制器属主管理、ALUA属性与路径选择策略配置和I/O重定向等模块进行了创新性的设计与实现.经过应用测试,该系统很好地解决了存储系统的路径故障迁移和故障恢复问题,并智能地实现了路径间I/O的负载均衡,极大地提高了性能和可靠性.     

QFMA:一种支持负载均衡的多属性资源定位方法

P2P技术是实现SOA去中心化的有效方法.在基于元数据的P2P系统中,描述资源属性的关键字分布和访问的不均匀性使某些元数据存储节点极易成为负载热点,严重影响了系统可用性.在MAAN基础上给出了一种支持负载均衡的多属性资源定位方法QFMA,将过载节点状态反馈到查询路径上,后续查询将根据反馈信息进行查询目标切换.分析和实验表明QFMA以O(logN)的路径长度实现资源的高效定位,并能够通过负载分流,有效缓解"热门"节点的负担,提高系统的负载均衡特性.     

基于相似负载的iSCSI透明可靠多播

提出一种针对iSCSI网络计算系统的I/O加速策略——基于相似负载的iSCSI透明可靠多播。通过对I/O请求数据块进行相似负载判定以及对原有iSCSI协议进行扩展,在iSCSI网络计算系统中构建数据传输双路径——iSCSI协议数据包路径和相似负载的多播路径,以提高网络计算数据的加载速度。测试结果表明,该策略能有效提升多个客户主机的并发I/O性能。     

SNFS并行文件系统负载均衡技术的研究与实现

在大规模集群系统的并行运算环境中,I/O效率一直是影响系统整体性能的关键因素,并行文件系统技术是目前解决I/O性能瓶颈的有效途径之一。介绍当前并行文件系统的发展现状以及并行文件系统的类型,阐述SNFS并行文件系统的架构以及负载均衡DLC(分布式LAN客户端)技术的实现原理,并给出大规模集群系统环境中SNFS文件系统负载均衡技术的实现方法,最后,通过实际应用分析说明该技术在提升I/O性能上的优势。     

基于动态副本技术的云存储负载均衡研究

以系统总响应时间最小化为目标,以文件热度为依据,提出了一种多时间窗负载均衡策略。在计算文件热度时,不仅考虑了访问的次数和大小,还将I/O访问时序引入到文件热度统计中,该方法能有效控制短时间突发性数据访问导致的不必要副本创建。在多时间窗负载均衡策略中,设置了三种不同大小的时间窗口,分别实现了存储节点负载均衡、文件副本的负载均衡以及低热度文件多余副本的删除工作。实验数据表明,多时间窗负载均衡策略能显著降低I/O访问响应时间。     

基于轮转部署的RAID6分布式存储系统扩容方案

随着用户数据和新型应用的爆炸式增长,存储系统需要更大的存储空间和更好的I/O性能,导致对原有存储系统进行扩容。研究基于RDP编码的存储系统的扩容问题。已有的扩容方案RS6、SDM等没有考虑到校验块的轮转部署与负载均衡等因素,导致扩容后的系统中各磁盘的负载不平衡。在基于校验块轮转部署的基础上,提出一种新型RDP扩容方案RSR。基于RSR的扩容方案,扩容后的系统中各磁盘上的数据块与校验块的分布都是均衡的。通过在Disksim上的一系列模拟实验证明,RSR的数据块和校验块迁移量上达到了最优,并且在扩容后的系统访问性能也接近于最优。     

基于集群的MPI主从式并行文件传输系统的研究与实现

研究并实现了一种基于PC集群系统的MPI主从式并行文件传输系统。通过引入一个监控节点实时监控当前各真实节点上的连接数、请求任务量以及各节点的实际处理能力,并衡量不同内容节点的负载,以实现集群内各节点负载均衡,从而更合理地实现并行文件I/O的任务分配。结果显示,该系统具有近似线性加速比,即文件I/O传输速度随着并行节点数量的增多而提高。     

Built-In Self-Test Techniques

A system that includes self-test features must have facilities for generating test patterns and analyzing the resultant circuit response. This article surveys the structures that are used to implement these self-test functions. The various techniques used to convert the system bistables into test scan paths are discussed. The addition of bistables associated with the I/O bonding pads so that the pads can be accessed via a scan path (external or boundary scan path) is described. Most designs use linear-feedback shift registers for both test pattern generation and response analysis. The various linear-feedback shift register designs for pseudorandom or pseudoexhaustive input test pattern generation and for output response signature analysis are presented.     

Built-In Self-Test Structures

A system that includes self-test features must have facilities for generating test patterns and analyzing the resultant circuit response. This article surveys the structures that are used to implement these self-test functions. The various techniques used to convert the system bistables into test scan paths are discussed. The addition of bistables associated with the I/O bonding pads so that the pads can be accessed via a scan path (external or boundary scan path) is described. Most designs use linear-feedback shift registers for both test pattern generation and response analysis. The various linear-feedback shift register designs for pseudorandom or pseudoexhaustive input test pattern generation and for output response signature analysis are presented.     

Man-machine interactive guidance for urban railway networks

A passenger requires precise and timely guidance information about his path from origin to destination on an urban railway network, e.g. the shortest time path and the minimal cost path. Such two paths are not easy to estimate because the former path is dynamically varied in time-dependent fashion by the ununiformity of train traffic density on time and by the mixture of different train traffic scheduling systems of several companies and the latter path may be composed of one or more lines operated by several companies with their different fare systems. This paper clarifies smooth and effective interaction steps for the guidance for urban railway networks, enumerates I/O devices suitable for the effective guidance, enumerates data items to be required for the effective guidance, clarifies the relationships among them, describes the problems in solving the shortest time path and the minimal cost path, shows our newly devised two analysis algorithms, and shows the overview of the pilot system of our man-machine guidance system in terms of a graphic display.     

基于ARIMA的存储优化算法设计与实现*

分析了SAN（storage area network）共享存储体系中I/O访问路径上可能存在的性能瓶颈,提出了采用ARIMA时间序列分析方法建立基于前馈的预测式控制机制,预测瓶颈发生趋势;通过改变存储子系统内的块映射关系来实现数据的迁移,减少I/O访问路径上发生性能瓶颈的可能性,有效提高了SAN的可靠性和可用性。     

SAN存储系统的I/O路径控制与管理

介绍SAN存储系统的I／O路径控制与管理技术．首先阐述基于QLA2300 HBA的在目标器和启动器模式下的固件和驱动程序的I／O通信过程；并进一步介绍SAN存储设备的LUN到SCSI启动器的动态映射和基于设备号的固定映射实现；最后说明一种基于I／O路径的高可用性技术;基于主从热备用的FAILOVER的实现方法．     

A concurrent solution for intra-cell flow path layouts and I/O point locations of cells in a cellular manufacturing system

In this paper, we study the I/O (Input/Output) point location problem and the intra-cell flow path layout problem of cells in a cellular manufacturing system. Traditional approaches have often solved these two problems as separate problems, despite they are mutually affected. As a result, the results obtained by traditional approaches may not be as desirable as expected. In this study, we propose a layout procedure that can solve these two problems concurrently, so that the sum of the inter-cell flow distance and the intra-cell flow distance can be minimized. We assume cells have been arranged along a straight-line inter-cell flow path. Furthermore, the machines’ positions on each cell’s intra-cell flow path have been determined, but the intra-cell flow path of each cell has not been placed on the shop floor yet. We also assume the configuration of intra-cell flow paths is serpentine. The proposed layout procedure classifies the flow distance incurred by inter-cell flow into five types and minimizes them with different solution procedures containing various linear programming models. The proposed layout procedure has four phases. At the first phase, we find each cell’s input and output points on the inter-cell flow path by considering only the inter-cell flow distance. At the second phase, we find the input and outpoint points on each cell’s intra-cell flow path by considering only the intra-cell flow distance. At the third phase, we use the points found in the previous two phases as references to help us correctly orient and arrange each cell’s intra-cell flow path on the shop floor. Finally, at the fourth phase, we find the accurate the input points and output points on each cell’s intra-cell flow path and the inter-cell flow path by simultaneously considering the inter-cell and the intra-cell flow distance. We use an example to illustrate the proposed layout procedure. The results of the example show that the proposed layout procedure can effectively find each cell’s I/O point locations and intra-cell flow path layout by considering both intra-cell and inter-cell flow distance at the same time.     

电子罗盘在智能吸尘器路径分析中的应用

在智能吸尘器开发和路径规划过程中,直线行走和转弯所产生的偏差是影响路径规划的主要因素.为了适应行走路径的多变性,将电子罗盘应用到智能吸尘器的控制系统中,由单片机通过I2C接口与电子罗盘进行通信,采用Zig Bee无线模块将数据传输到上位机,通过Matlab进行仿真实验,并对直线行走和转弯偏差进行分析研究.实验过程精确得出了智能吸尘器的方位信息和行走路径,有利于优化路径规划算法和提高路径规划效率.