一种新的服务器集群系统的设计与实现

互联网的飞速发展给我们带来极大便利的同时，也对网络服务器的性能提出了新的挑战。集群技术已成为解决服务器瓶颂问题的有效手段。本文在对服务器集群系统存在的瓶颈问题进行分析的基础上，提出了一种新的服务器集群系统解决方案。该方案通过对传统socket通讯模型进行扩展，并结合直接路由技术，有效地减轻虚拟服务器的负载；同时，通过采用主动自调度策略以解决真实服务器的瓶颈问题，对原型的测试表明该模型是可行的，且提高了服务器集群系统的性能。     

基于互联网的电网监测诊断系统

为了实现远程监测诊断，在TCP／IP协议下，利用有效的网络资源，ASP和socket技术，采用易于扩展的客户／服务器结构模型来设计系统，并在Internet和Windows环境下，实现远程电网监测诊断系统。     

基于MSRP的离线消息服务系统的研究与设计

即时消息作为一种新的通信方式,业务扩展范围非常广泛。提出了一种基于消息会话中继协议,即MSRP协议的通信服务器集群的实现框架,能够支持SIP系统中的离线消息业务。首先针对MSRP协议工作在会话模式下的特性,提出了服务系统的整体设计思想,并研究分析了转储和推送离线消息的信令流程。然后提出了通信服务器集群的实现方案和集群内部的通信框架。服务系统能够在SIP软终端的配合下处理基于MSRP的离线消息业务。     

基于Netlink机制的1553B协议通用接口设计

Netlink是Linux系统下的一种全新的协议族,其实现了进程间通信功能.文中在参考了linux操作系统下Netlink机制和1553B协议的实现,研究了将1553B协议和基于Netlink机制的socket套接字相结合之后,设计了一套基于Netlink机制的1553B协议通用接口.该套接口的实现是通过Netlink通信机制对socket下的协议栈进行了扩展和定义.文中实现了基于Netlink机制下使用socket API传输1553B数据的功能.通过实验验证了通用接口的便利性.     

OnceDeep数据交换服务器集群系统的设计与实现

数据交换中一般存在数据中心。中心处理的并发任务量高,对服务器性能和可靠性要求高,往往会成为数据交换的瓶颈。为了提高数据交换平台的数据中心的性能、可靠性,并降低管理成本,设计和实现了Once Deep数据交换服务器集群系统。基于现有的数据交换平台Once Deep,使用Shoal集群框架实现对Once Deep服务器集群的管理。讨论集群环境下数据交换流程的设计。针对数据交换任务的特点设计基于预测的动态负载均衡算法,制定任务失效的恢复策略。测试表明,集群系统较现有数据交换服务器在性能上有很大提高,并具有较好的扩展能力。     

LVS负载均衡调度算法的改进及实现

采用服务器集群架构提供服务成为互联网服务业中普遍采用的策略,目前使用得比较广泛的网络负载均衡集群是Linux虚拟服务器集群。优秀的负载均衡算法可以将用户请求合理地分配到集群中的真实服务器中．提高集群中服务器的利用率和集群系统的吞吐量。针对LVS默认算法WLC算法的不足之处,对WLC算法进行改进．设计并实现一种基于反馈式的负载均衡算法。实验证明,改进算法能够增大集群的吞吐量,提升集群的整体性能。     

集群系统负载均衡性能测试研究

分析影响集群系统性能的关键因素,提出在Linux下架设负载均衡系统,获取集群系统关键性能参数,加权计算真实服务器的负载。根据服务器负载由负载均衡器动态分配连接请求,使集群达到负载均衡。使用不同的客户端进行测试,分析比较不同测试软件的测试结果,为改进集群系统的负载均衡性能提供支持。     

DCFS2的元数据一致性策略

随着集群应用对机群文件系统的性能、容量和规模等需求的日益增长,采用多元数据服务器是机群文件系统发展的必然趋势．基于多元数据服务器的分布式元数据处理是文件系统研究的一个重要问题．机群文件系统DCFS2采用分布式日志技术和改进的两阶段提交协议解决了分布式元数据处理下元数据的一致性问题．性能测试结果表明,DCFS2所采用的基于分布式日志的元数据处理策略能够提供高的I／O性能,并能够保证在元数据服务器失效后文件系统快速恢复．     

Linux集群实时监控系统的一种实现方法

随着云计算技术的日益发展, Linux集群以造价低廉、易于扩充等优势得到了愈来愈广泛的应用. 为了更好地发挥集群性能, 充分利用集群节点的资源, 对集群性能进行实时监控是很有必要的. 提出了一种Linux集群监控器设计与实现方法. 该方法通过每隔一段时间采集节点机/proc虚拟文件系统中的信息, 如CPU和内存使用情况等. 经过过滤后, 通过socket传输给监控服务器. 论文首先给出了监控器的总体设计方案, 整个监控系统由守护在管理节点上的信息管理服务器进程和运行在各个计算节点上的采集器进程组成. 然后分采集器和信息管理器两大部分, 分别介绍了其具体的设计框架和其采用的关键技术. 采集器分主要由信息采集、信息处理和信息传送3 个模块组成, 分别采用3 个线程来完成. 信息管理器采用了线程池技术, 用以接受采集器发送过来的传输请求. 实践证明, 该系统可以很好地满足实时监控Linux 集群性能的需要.     

Linux集群系统性能的实时监测及其可视化研究

在研究如何获取单个Linux集群服务器节点性能参数的基础上,利用CGI(Common Gateway Interface)技术,通过HTTP协议实现了异步采集Linux集群服务器节点性能参数的方法.在监控节点上利用QT编程实现Linux集群系统性能的实时监测及其可视化.通过定时器、CGI技术、HTTP协议、专用算法的有机结合,实现无序返回结果的有序化,达到实时、异步采集Linux集群服务器节点性能参数目的,是一种具有创新性的Linux集群系统性能实时监测方法.与传统的网络监测方法相比,具有占用系统资源少、可靠、实用的特点,可广泛应用于各种Linux集群系统,也为下一步实施Web服务器动态负载均衡打下基础.     

影响多媒体服务器性能的关键因素研究

在构建大规模视频服务系统时 ,基于层次型多服务器群的体系结构在吞吐率、可扩展性、经济性等方面都有其突出的优势 ,尤其适合于在因特网上的应用 .但是 ,要充分发挥和提高视频服务系统的性能 ,还要针对一些主要的瓶颈(如服务器磁盘 I/ O带宽与网络带宽 ) ,解决好一系列的问题 .本文分析了影响多媒体视频服务器性能的一些主要因素 ,如视频服务器的体系结构、服务器与客户端之间的数据传送方式、媒体数据在视频服务器存储子系统中的分布与放置方式、对磁盘访问请求的调度、单服务器中的缓存及多服务器间协同缓存的管理、接入控制策略、流调度策略等 ,这些因素对视频服务器的性能与吞吐率有着极大的影响 .本文还介绍了一些适用于大规模视频服务系统的性能优化技术 ,如广播、批处理等流调度策略 .在构建视频服务器系统时 ,只有综合考虑这些因素 ,才能真正提高服务器乃至整个视频服务系统的吞吐率 ,并较好地满足客户的 Qo S要求     

分布式数据流处理系统的动态负载平衡技术

设计了一种新的大规模分布式数据流处理系统的体系结构。系统由一组异构的服务器集群组成，负载在每个服务器集群内部多台同构的服务器之间获得平衡，从而达到整个系统的负载平衡。集群设计的主要目标之一是以资源换性能，服务器集群中服务器的最大数目足够保证系统不再发生过载现象，不再需要会降低性能的卸载技术。而且投入运行的服务器的数目根据实际的系统负载来决定，负载较轻时，一部分服务器可以进入休眠状态来减少能源的消耗。根据系统动态增减服务器的特点，设计了全新的初始化算法、动态负载平衡算法。与以前的分布式数据流处理系统相比，由于单个集群的服务器的数目大大减少，算法复杂性降低、速度加快、优化的空间增大。     

Wireless resource management mechanism with green communication for multimedia streaming

In the face of massive parallel multimedia streaming and user access, multimedia servers are often in an overload state, resulting in the delay of service response and the low utilization of wireless resources, which makes it is difficult to satisfy the user experience quality. Aiming at the problems of low utilization rate of multimedia communication resources and large computing load of servers, this paper proposes a self management mechanism and architecture of wireless resources based on multimedia flow green communication. First, based on the combination of multimedia server, relay base station and user cluster, a multimedia green communication system architecture is built based on the comprehensive utilization rate of multimedia communication, and a cluster green communication control algorithm is proposed. Secondly, aiming at the dynamic service demand and asynchronous multimedia communication environment, aiming at ensuring the balance of resource allocation and accelerating the speed of resource allocation, we build a dynamic multimedia wireless resource architecture. Finally, the experimental results of statistics and analysis, from the server in different scale parallel multimedia streams under different scale delay, number of users relay network free resources proportion, user satisfaction, packet loss rate and other performance show that the proposed algorithm is effective and feasible.

     

Exploring High-Performance Architecture for Data Center Networks

As a critical infrastructure of cloud computing, data center networks (DCNs) directly determine the service performance of data centers, which provide computing services for various applications such as big data processing and artificial intelligence. However, current architectures of data center networks suffer from a long routing path and a low fault tolerance between source and destination servers, which is hard to satisfy the requirements of high-performance data center networks. Based on dual-port servers and Clos network structure, this paper proposed a novel architecture to construct high-performance data center networks. Logically, the proposed architecture is constructed by inserting a dual-port server into each pair of adjacent switches in the fabric of switches, where switches are connected in the form of a ring Clos structure. We describe the structural properties of in terms of network scale, bisection bandwidth, and network diameter. architecture inherits characteristics of its embedded Clos network, which can accommodate a large number of servers with a small average path length. The proposed architecture embraces a high fault tolerance, which adapts to the construction of various data center networks. For example, the average path length between servers is 3.44, and the standardized bisection bandwidth is 0.8 in (32, 5). The result of numerical experiments shows that enjoys a small average path length and a high network fault tolerance, which is essential in the construction of high-performance data center networks.     

Video placement and configuration of distributed video servers on cable TV networks

A large-scale, distributed video-on-demand (VOD) system allows geographically dispersed residential and business users to access video services, such as movies and other multimedia programs or documents on demand from video servers on a high-speed network. In this paper, we first demonstrate through analysis and simulation the need for a hierarchical architecture for the VOD distribution network.We then assume a hierarchical architecture, which fits the existing tree topology used in today's cable TV (CATV) hybrid fiber/coaxial (HFC) distribution networks. We develop a model for the video program placement, configuration, and performance evaluation of such systems. Our approach takes into account the user behavior, the fact that the user requests are transmitted over a shared channel before reaching the video server containing the requested program, the fact that the input/output (I/O) capacity of the video servers is the costlier resource, and finally the communication cost. In addition, our model employs batching of user requests at the video servers. We study the effect of batching on the performance of the video servers and on the quality of service (QoS) delivered to the user, and we contribute dynamic batching policies which improve server utilization, user QoS, and lower the servers' cost. The evaluation is based on an extensive analytical and simulation study.     

Secure spread: an integrated architecture for secure group communication

Group communication systems are high-availability distributed systems providing reliable and ordered message delivery, as well as a membership service, to group-oriented applications. Many such systems are built using a distributed client-server architecture where a relatively small set of servers provide service to numerous clients. In this work, we show how group communication systems can be enhanced with security services without sacrificing robustness and performance. More specifically, we propose several integrated security architectures for distributed client-server group communication systems. In an integrated architecture, security services are implemented in servers, in contrast to a layered architecture, where the same services are implemented in clients. We discuss performance and accompanying trust issues of each proposed architecture and present experimental results that demonstrate the superior scalability of an integrated architecture.     

Performance analysis of a pull-based parallel video server

In conventional video-on-demand systems, video data are stored in a video server for delivery to multiple receivers over a communications network. The video server's hardware limits the maximum storage capacity as well as the maximum number of video sessions that can concurrently be delivered. Clearly, these limits will eventually be exceeded by the growing need for better video quality and larger user population. This paper studies a parallel video server architecture that exploits server parallelism to achieve incremental scalability. First, unlike data partition and replication, the architecture employs data striping at the server level to achieve fine-grain load balancing across multiple servers. Second, a client-pull service model is employed to eliminate the need for interserver synchronization. Third, an admission-scheduling algorithm is proposed to further control the instantaneous load at each server so that linear scalability can be achieved. This paper analyzes the performance of the architecture by deriving bounds for server service delay, client buffer requirement, prefetch delay, and scheduling delay. These performance metrics and design tradeoffs are further evaluated using numerical examples. Our results show that the proposed parallel video server architecture can be linearly scaled up to more concurrent users simply by adding more servers and redistributing the video data among the servers     

Improving availability and performance with application-specific data replication

The emerging edge services architecture promises to improve the availability and performance of Web services by replicating servers at geographically distributed sites. A key challenge in such systems is data replication and consistency, so that edge server code can manipulate shared data without suffering the availability and performance penalties that would be incurred by accessing a traditional centralized database. This work explores using a distributed object architecture to build an edge service data replication system for an e-commerce application, the TPC-W benchmark, which simulates an online bookstore. We take advantage of application-specific semantics to design distributed objects that each manages a specific subset of shared information using simple and effective consistency models. Our experimental results show that by slightly relaxing consistency within individual distributed objects, our application realizes both high availability and excellent performance. For example, in one experiment, we find that our object-based edge server system provides five times better response time over a traditional centralized cluster architecture and a factor of nine improvement over an edge service system that distributes code but retains a centralized database.