基于linux的高可用负载均衡集群系统的应用

通过分析Li nux集群系统关键技术,设计了一种基于LVS和Keepalived的高可用服务器集群系统的实现方案,可以提高集群系统的负载均衡、高可用性和可扩展性,为集群系统的构建提供了较好的理论和实践参考依据.     

利用DRBD和Pacemaker技术构建高可用数据容灾备份系统

为充分保证数据信息安全,提高数据中心容灾备份能力,以DRBD和Pacemaker技术为基础构建具有高可用性的数据容灾备份系统,实现生产数据在本地、异地之间三台服务器的镜像复制,并且实现应用和数据两个级别的高可用(HA),解决目前主流SAN存储环境下共享磁盘阵列的单点故障威胁,有效满足不断提升的数据恢复RTO和RPO的要求.本论述为数据中心业务系统高可用和数据异地备份提出了低成本的技术方案.     

支持海量数据的分布式数据库架构设计与验证

结合电信行业实际业务需求,利用数据库代理,设计出了能够提供强一致性、高可用性并支持弹性水平扩展能力的分布式数据库架构.验证结果表明,对于分布式数据库采用数据库代理可满足高可用性与弹性水平扩展的设计要求,实际部署中,双Master部署模式性能体现较佳,读写分离的部署模式、读写操作部署在一台设备性能下降明显,说明数据库代理可以实现高可用性的分布式数据库架构,各类部署架构中影响性能的是磁盘I/O.     

可扩展分布式关系型云数据库方案

为满足云数据库高并发、高可扩展和高可用性的需求,在分析各种关系型和NOSQL数据库的基础上,借鉴关系型数据的便捷性与NOSQL的可扩展性,提出了一种可扩展性的关系型云数据库方案.该方案提出了全新的系统架构、数据库读写流程、数据合并流程、数据模型和数据结构与存储,并对其系统架构理论存在瓶颈进行分析.最后对数据一致性、可用性和线上运行性能进行分析,结果表明此方案可行.     

高可用冗余热切换CompactPCI系统总线仲裁设计

CompactPCI(以下简称CPCI)高可用冗余热插拔系统平台，采用l l双主系统槽冗余热切换结构，支持主系统槽冗余备份、故障板隔离、热切换以及动态配置，达到99．999％的高可用性．高可用系统总线仲裁器的设计是保障该系统热切换的关键逻辑，其性能直接影响整个系统的可靠性和传输带宽等指标，本文提出了一种CPCI总线仲裁器，并在EPLD(erasmble programmable logic device可编程逻辑器件)中实现该逻辑．实际测量的结果表明该方案是一种公平、高效的总线仲裁器，完全满足高可用CPCI系统平台的要求．     

高可用数据库系统中的分布式一致性协议

可用性和一致性是分布式数据库系统中的两个重要特性和基础,需要借助分布式一致性协议来保证.保证一致性需要使用一致性协议为并发的事务更新操作确定一个全局的执行顺序,并协调局部状态和全局状态不断地达到动态一致.可用性的实现,需要一致性协议协调多副本之间的一致来实现主备节点的无缝切换.可见,分布式一致性协议是高可用数据库系统的实现基础.本文梳理、综述了经典的分布式一致性协议以及一致性协议在高可用数据库系统中的主要应用,并对分布式一致性协议的实现代价和局限性进行了分析与评估.     

Redis可扩展与高效复制方案的设计与实现简

为了解决Redis数据库复制性能差和扩展性差的问题,该文设计了一个Redis可扩展与高效复制方案,即基于文件共享的主从复制和基于一致性哈希的集群(RSCCH-Redis,Replication on Share and Clusters on Consistent Hash of Redis)方案.该方案在Redis应用中引入了一致性哈希以实现可扩展性及引入了基于文件共享的主从复制功能来提高复制性能;采用一致性哈希作为映射方式,并在其中引入了虚拟节点,这样不但保证了映射关系的单调性与分散性,还保证了映射的负载均衡性;采用文件共享的主从复制方式,可以避免初次复制时大量的数据传输,减轻网络压力,加快复制速度,从而减少故障恢复时间.实验数据表明,该文设计的Redis高可用方案RSCCH-Redis不但解决了Redis数据库复制性能差的问题,而且有着良好的可扩展性.     

HANDY集群文件系统

针对当前集群文件系统缺乏动态扩展性和高可用性的不足,提出了一种基于逻辑矢量环结构的集群文件系统HANDY.系统利用逻辑矢量环实现动态扩展和资源的动态管理,采用了分布式元数据管理策略,引入邻接复制技术实现元数据的容错,通过可定制的数据存放策略满足不同应用的数据存储需求.测试结果表明,基于环状结构的系统HANDY具有良好的动态扩展性和高可用性.     

Redis可扩展与高效复制方案的设计与实现

为了解决Redis数据库复制性能差和扩展性差的问题,该文设计了一个Redis可扩展与高效复制方案,即基于文件共享的主从复制和基于一致性哈希的集群(RSCCH-Redis,Replication on Share and Clusters on Consistent Hash of Redis)方案.该方案在Redis应用中引入了一致性哈希以实现可扩展性及引入了基于文件共享的主从复制功能来提高复制性能;采用一致性哈希作为映射方式,并在其中引入了虚拟节点,这样不但保证了映射关系的单调性与分散性,还保证了映射的负载均衡性;采用文件共享的主从复制方式,可以避免初次复制时大量的数据传输,减轻网络压力,加快复制速度,从而减少故障恢复时间.实验数据表明,该文设计的Redis高可用方案RSCCH-Redis不但解决了Redis数据库复制性能差的问题,而且有着良好的可扩展性.     

基于Raft一致性协议的高可用性实现

随着互联网的快速发展和大数据时代的来临,传统数据库的局限性开始逐渐显现,而支持海量数据存储和高并发访问的分布式数据库系统越来越流行.在此背景下阿里巴巴集团研发了一款适用于海量数据存储的分布式数据库系统(OceanBase),并提供单集群和多集群两种部署模式.但多集群部署模式下的可用性较低,无法满足关键性应用的需求,包括:发生故障时不支持主备集群的自动切换;主备集群之间无法保证日志的强同步.针对上述问题,本文分析了传统数据库的高可用方案,针对OceanBase架构的特点,结合了Raft算法的思想,设计并实现了基于时间戳的分布式选举模块、自动化的集群切换模块和基于QUORUM策略的日志强同步模块.经实验验证,以上模块的实现能够提高系统整体的可用性.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that