IP存储广域网的性能研究

由于光纤的传输距离有限，使FC SAN的连接距离受到限制。IP存储广域网利用IP网络存储技术扩展了主机与存储设备的连接距离，提供了广域网范围内块级数据的访问。文中对IP存储广域网的结构、性能进行了研究，提出了IP存储广域网的系统性能评价模型，为评价和改进IP存储广域网的系统性能提供了理论依据。理论分析和测试结果表明，虽然影响IP存储广域网性能的因素有很多，但当网络带宽低于存储设备吞吐率时，IP广域网网络带宽成为决定IP存储广域网最大系统吞吐率的决定因素。     

基于iSCSI的IP存储广城网性能分析

随着远程容灾、内容分发、数据网格等的不断应用,要求数据存储的范围从局域网拓展到广域网。在SNIA共享存储体系结构的基础上,提出了基于iSCSI协议的IP存储广域网的共享存储模型,并利用iSCSI软件实现方式,基于网络RAID设计实现了IP存储广域网系统。通过实验测试,研究了网络带宽、网络延迟和丢包率对IP存储广域网性能的影响。实验结果表明：IP存储广域网的性能随着网络性能的下降而降低。     

一种IP网络存储协议iBDTP的设计与实现

目前可用于IP存储广域网的IP网络存储协议包括iSCSI、HyperSCSI、ENBD等,它们在支持多类型设备接口、支持TCP/IP协议以及设备自动发现机制上存在诸多不足。为了克服这些不足,文章设计了一种iBDTP协议,它支持多种类型的设备接口,并在IP广域网范围内具有设备的自动发现机制。此外,在iBDTP基础上,该文利用基本的IP广域网结构,构建了IP存储广域网,并对基于iBDTP协议的IP存储广域网的性能进行了分析。     

基于随机Petri网的IP-SWAN系统性能评价

在分析基于iSCSI协议的IP存储广域网(IP-SWAN)的数据传输流程的基础上,提出了IP-SWAN系统的随机Petri网模型和一种新的基于变迁的串并联等价变换计算系统I/O响应时间的SPNA方法。基于SPNA方法的性能分析和预测结果表明,在低速网环境下,网络传输速率是系统性能的主要瓶颈,提高网络带宽可以有效地改进整个系统性能。在高速网环境下,提高中心节点的读缓存命中率和CPU处理效率,可以降低系统的I/O响应时间。     

基于iSCSI的IP存储广域网可用性分析

随着远程容灾、内容分发、数据网格等不断发展,要求数据存储的范围从局域网拓展到广域网.本文提出了基于iSCSI协议的IP存储广域网系统模型,并利用一种新的可用性度量标准-任务完成概率,分析了IP存储广域网的可用性.分析结果表明：当任务数量达到百万时,系统完成概率在99.7%左右.     

基于WAN的网络软RAID系统性能的研究

当前绝大多数网络存储系统都是通过高速网络进行连接的。论文设计并构建了基于低速WAN的网络软RAID系统(NSRAID),研究了广域网环境下影响网络存储系统性能的主要因素。同时,以网络负载的角度分析了远程存储节点数、网络存储协议和数据布局方式影响系统性能的内在原因。在此基础上,针对广域网不同的网络性能提出了提高网络软RAID系统性能的方法。     

IP存储广域网的I/O响应时间分析

以往对网络存储系统的性能分析大都集中在定性研究,定量分析模型很少。在分析基于iSCSI协议的IP存储广域网(IP-SWAN)的数据传输流程的基础上,建立了该系统的Petri网模型。利用Petri网模型的特点,在理论上计算了IP-SWAN系统的I/O响应时间,并分析了各参数对系统性能的影响,提出了改进IP-SWAN系统性能的方法。     

万兆以太网技术与iSCSI技术的完美融合

华硕新近推出的i316-A1／0141AR是一款实现了万兆以太网技术与iSCSI技术的完美融合的3U存储系统，可为企业提供稳定与性能并重的企业存储环境，同时使SAN得以延伸至基于IP技术的广域网上。     

网络RAID存储系统边界性能研究

目前针对网络存储系统性能的研究大都集中在定性研究方面,缺乏有效的定量分析方法和模型．在有限容量闭合排队网络理论的基础上,提出了网络RAID存储系统性能的定量分析模型．并提出了一种新的计算有限容量闭合排队网络系统边界性能的分析方法-APBA法,和其他近似分析方法相比,APBA法的计算时间复杂度更低．测试结果表明,通过利用APBA方法,由网络RAID存储系统的性能定量分析模型获得的系统性能值,可以有效反映网络RAID存储系统在轻载区、重载区和过载区的性能边界,以及系统的最大负载量．     

基于VIA的存储局域网的设计与研究

存储局域网（Storage Area Network，SAN）以其自身的优势越来越多的应用在企业数据存储领域．目前主流的SAN包括采用FC（Fibre Channel）协议的FC SAN与采用IP（Internet Protocol）协议的IP SAN．FC SAN存在价格昂贵，互操作性差等不足；IP SAN虽然价格低廉，但IP协议本身并不适合于传输存储I／O数据．为了克服这些不足，本文探讨了一种用VIA（Virtual Interface Architecture）协议替代IP协议的VIA-SAN，并通过实验分析比较了VIA协议相对于IP协议的性能优势．     

基于构件的软件性能模型及评估技术研究

该文讲述了在基于构件的软件开发中,建立应用系统的性能模型,以及对系统的性能进行预测和评估的方法,并介绍了构建一个满足预期性能目标的软件系统的步骤。     

一种并行程序性能工具的研究与实现

随着高性能计算技术的不断发展,并行程序的设计、调试、优化逐渐成为并行技术应用的关键,而性能工具在提高并行程序的执行效率方面发挥着重要的作用。本文阐述了并行程序性能工具的系统结构,以及各个模块功能的原理,并实现了一个基于MPI消息统计的性能工具。     

Prescribed performance control approaches,applications and challenges: A comprehensive survey

As to control systems, transient performance is as important as steady-state performance. For some special dynamic systems, transient performance is a more prior index in comparison with the steady-state one. Prescribed performance control (PPC) has been proved to be a powerful tool that guarantees control system outputs/errors with desired transient performance as well as steady-state performance. The purpose of this paper is to give a comprehensive review on the latest developments of PPC theories and applications. The existing performance functions are classified into five different categories, and their features are comprehensively compared, providing a useful guidance for further applications. Then, the latest developments of PPC's applications in all kinds of control systems are recalled. Specially, the faced challenges and theoretical defects of PPC are discussed, which is expected to point out the further research direction for PPC.     

On the Performance Regularity of Web Servers

The performance regularity is concerned with the overall performance behavior of a system in the full spectrum of working area. Such a performance characteristic is generally overlooked and does not receive proper attention. The aim of this paper is twofold. First, it raises awareness of the importance of the performance regularity of a Web server. Secondly, it introduces the Gini performance coefficient (GPC) as a scale-invariant metric for measuring the performance regularity. In this paper, we present the theorems that relate the performance regularity of a Web server to the GPC, thereby providing a quantitative yardstick that complements the system capacity metric such as maximum throughput for measuring the system performance. To illustrate the use of the proposed approach, we calculate the values of GPC for several representative systems that were used in the public SPECweb96 benchmark study. The results are completely in line with our theoretical analysis.     

Application of Relational Interval Arithmetic to Computer Performance Analysis: a Survey

This paper presents a survey of the existing work in the area of interval-based performance analysis of computing systems. Intervals in performance analysis is required when uncertainties or variabilities exist in the workload parameters for the performance model of the system. Intervals are also useful for computing upper and lower bounds on system performance. Most conventional analytic models accept a set of single valued parameters and produce a single valued model output. Adaptation of these existing models to handle interval parameters require new techniques that use interval arithmetic. Experiences with relational interval arithmetic provided by a constraint logic programming language in solving a number of performance analysis problems in conventional multiprogrammed computers as well as distributed processing systems are described.     

系统性能极限理论的回顾和展望

描述了系统性能极限理论的研究对象、背景和意义,并简要介绍了系统性能极限理论所涉及到的四个相关问题,如:左可逆与右可逆系统、零点与零点方向、极点与极点方向以及灵敏度函数与互补灵敏度函数.同时,从H2型性能极限、频域及H∞型性能极限、时域及其他性能极限三方面综述了系统性能极限理论的研究现状,并对其未来的发展进行了展望.     

PHOEBE: an automation framework for the effective usage of diagnosis tools in the performance testing of clustered systems

The identification of performance issues and the diagnosis of their root causes are time‐consuming and complex tasks, especially in clustered environments. To simplify these tasks, researchers have been developing tools with built‐in expertise for practitioners. However, various limitations exist in these tools that prevent their efficient usage in the performance testing of clusters (e.g. the need of manually analysing huge volumes of distributed results). In a previous work, we introduced a policy‐based adaptive framework (PHOEBE) that automates the usage of diagnosis tools in the performance testing of clustered systems, in order to improve a tester's productivity, by decreasing the effort and expertise needed to effectively use such tools. This paper extends that work by broadening the set of policies available in PHOEBE, as well as by performing a comprehensive assessment of PHOEBE in terms of its benefits, costs and generality (with respect to the used diagnosis tool). The performed evaluation involved a set of experiments in assessing the different trade‐offs commonly experienced by a tester when using a performance diagnosis tool, as well as the time savings that PHOEBE can bring to the performance testing and analysis processes. Our results have shown that PHOEBE can drastically reduce the effort required by a tester to do performance testing and analysis in a cluster. PHOEBE also exhibited consistent behaviour (i.e. similar time‐savings and resource utilisations), when applied to a set of commonly used diagnosis tools, demonstrating its generality. Finally, PHOEBE proved to be capable of simplifying the configuration of a diagnosis tool. This was achieved by addressing the identified trade‐offs without the need for manual intervention from the tester. Copyright © 2017 John Wiley & Sons, Ltd.     

一种新的计算机抗攻击自身免疫模型

提出了一种新的计算机抗攻击自身免疫模型,形式化地阐述了模型如何使得不合法的程序和代码不能够执行,合法的程序和代码不能够执行未授权访问;合法的程序和代码的可疑行为受到严格的控制但是可以根据不同的阈值来保证实用性。这种模型不需要计算和识别计算机攻击的具体特征,而通过直接消除攻击能够实施破坏和传播的前提条件,使得计算机系统对攻击具备自身免疫能力。     

军用飞机预测与健康管理系统性能度量体系研究

基于健康退化曲线对军用飞机故障预测与健康管理( PHM)技术的内涵、基本功能和能力需求进行探讨,在此基础上,以科学评价PHM( prognostics and health management)系统的诊断和预测能力为目标,从能力需求出发提出PHM系统性能度量方法体系(包括诊断性能度量、预测性能度量以及综合度量),并对...     

面向对象冗余服务系统的性能分析与测试

通过对面向对象冗余服务系统的性能指标分析 ,结合实际应用中用户最为关心的性能价格比问题 ,利用数学分析模型 ,找出了满足冗余系统服务的最优解 ,并在此基础之上 ,对冗余系统的性能进行了分析与测试