[泛读]4篇Web Service Replication方面论文
Replication简介:
"Replication is the process of sharing information so as to ensure consistency between redundant resources, such as software or hardware components, to improve reliability, fault-tolerance, or accessibility." (wikipedia)
replication技术的目的主要是用于提高分布式系统(distributed object, database, file system等)的可依赖性(dependability), 依赖于冗余资源, 需要维护这些资源间的一致性.
按照复制的对象, 可分为data replication与computation replication两种.
按照实现方式, 可分为active replication与passive replication两种.
详见 http://en.wikipedia.org/wiki/Replication_(computer_science)
论文(一)
OSRAEL J, FROIHOFER L, GOESCHKA K M. What service replication middleware can learn from object replication middleware [C]// Proceedings of the 1st Workshop on Middleware for Service Oriented Computing. Melbourne, Australia: Association for Computing Machinery, 2006: 18-23
(1) 本文认为SO系统中replication尚处于起步阶段. 从架构(architectural)层次, 将现有的一些service replication middleware, 与object replication middleware进行了比较.
得到的结果是: SO系统中与分布式对象系统中的replication middleware有很多共同点, 存在的些许区别是由replicated entity的粒度和不同的transaction模型引起的.
(2) 现有的SO replication middleware
a)primary-backup replication middleware: "Fault tolerant web service"
b)active replication middleware: "WS-Replication: a framework for highly available web services", "A middleware for replicated Web services"
(3) 对于stateless service的replication比较简单, 难点主要在于针对stateful service的replication.
(4) 提取了6种architectural units (适用于object and service replication middleware):
Multicast service
monitoring service
replication manager
replication protocol unit
invocation service
transaction service(optional)
(5) 与WSC无关; 只关注dependability, 与QoS无关
论文(二)
LIANG D, FANG C L, CHEN C et.al. Fault tolerant Web service [C]// Proceedings of the Tenth Asia-Pacific Software Engineering Conference Software Engineering Conference (APSEC). Washington, DC: IEEE Computer Society, 2003: 310-319
本文gs: 32
(1) 提出了一种fault tolerant web service (FT-SOAP), 在消息层(SOAP)截获用户请求; 如果请求的WS fail了, 就自动重定向到backup WS. 本文的版面有点乱.
(2) 不涉及stateful WS; 不涉及WSC, QoS; 针对的是单个服务的fault tolerant; 适用replication manager生成备份服务, 不支持服务的动态发现等
论文(三)
YE X, SHEN Y. A Middleware for Replicated Web Services [C]// IEEE International Conference on Web Services (ICWS). Los Alamitos: IEEE Computer Society, 2005: 631-638
(1)提出了一个基于active replication, 支持reliable web service的middleware. 这个middleware负责维护replicas的状态.
使用这个middleware, 现有的单线程WS无需更改实现即可被复制到不同的站点.
每个replica包括两个实体: proxy service site(PWSS)和普通的web service site(WSS). 用户通过PWSS发送请求, PWSS负责维护对应的WSS的一致性和出错处理.
(2) 不涉及WSC QoS
论文(四)
SALAS J, PEREZ-SORROSAL F, PATINO-MARTINEZ M, et.al. WS-replication: a framework for highly available web services [C]// Proceedings of the 15th international conference on World Wide Web (WWW). Edinburgh, Scotland: Association for Computing Machinery, 2006: 357 - 366
(1) 本文提出了WS-Replication架构(infrastructure), 用于WAN环境中WS的replication.
WS-Replication的目的是使WS具有高度的availability, 从而能够满足mission critical system的需求.
这个架构基于group communication WS, WS-Multicast. WS-Multicast的传输是基于SOAP, 依赖WS进行跨组织的交互.
WS-Replication中采用了active replication的方式.
这四篇论文看的都比较粗略, 只是了解了一下论文的大概工作, 没有通读全文. 读了之后, 对WS replication有以下印象:
1. 作为replica的web services一般都是同一份实现, 需要维护保证代码和状态的一致性
2. WS不是动态发现的
3. 不是在WSC的场景下讨论, 主要针对WS的可靠性, 不涉及其他QoS
4. 都是通过middleware来支持web service replication
5. 需要考虑replica的location
"Replication is the process of sharing information so as to ensure consistency between redundant resources, such as software or hardware components, to improve reliability, fault-tolerance, or accessibility." (wikipedia)
replication技术的目的主要是用于提高分布式系统(distributed object, database, file system等)的可依赖性(dependability), 依赖于冗余资源, 需要维护这些资源间的一致性.
按照复制的对象, 可分为data replication与computation replication两种.
按照实现方式, 可分为active replication与passive replication两种.
详见 http://en.wikipedia.org/wiki/Replication_(computer_science)
论文(一)
OSRAEL J, FROIHOFER L, GOESCHKA K M. What service replication middleware can learn from object replication middleware [C]// Proceedings of the 1st Workshop on Middleware for Service Oriented Computing. Melbourne, Australia: Association for Computing Machinery, 2006: 18-23
(1) 本文认为SO系统中replication尚处于起步阶段. 从架构(architectural)层次, 将现有的一些service replication middleware, 与object replication middleware进行了比较.
得到的结果是: SO系统中与分布式对象系统中的replication middleware有很多共同点, 存在的些许区别是由replicated entity的粒度和不同的transaction模型引起的.
(2) 现有的SO replication middleware
a)primary-backup replication middleware: "Fault tolerant web service"
b)active replication middleware: "WS-Replication: a framework for highly available web services", "A middleware for replicated Web services"
(3) 对于stateless service的replication比较简单, 难点主要在于针对stateful service的replication.
(4) 提取了6种architectural units (适用于object and service replication middleware):
Multicast service
monitoring service
replication manager
replication protocol unit
invocation service
transaction service(optional)
(5) 与WSC无关; 只关注dependability, 与QoS无关
论文(二)
LIANG D, FANG C L, CHEN C et.al. Fault tolerant Web service [C]// Proceedings of the Tenth Asia-Pacific Software Engineering Conference Software Engineering Conference (APSEC). Washington, DC: IEEE Computer Society, 2003: 310-319
本文gs: 32
(1) 提出了一种fault tolerant web service (FT-SOAP), 在消息层(SOAP)截获用户请求; 如果请求的WS fail了, 就自动重定向到backup WS. 本文的版面有点乱.
(2) 不涉及stateful WS; 不涉及WSC, QoS; 针对的是单个服务的fault tolerant; 适用replication manager生成备份服务, 不支持服务的动态发现等
论文(三)
YE X, SHEN Y. A Middleware for Replicated Web Services [C]// IEEE International Conference on Web Services (ICWS). Los Alamitos: IEEE Computer Society, 2005: 631-638
(1)提出了一个基于active replication, 支持reliable web service的middleware. 这个middleware负责维护replicas的状态.
使用这个middleware, 现有的单线程WS无需更改实现即可被复制到不同的站点.
每个replica包括两个实体: proxy service site(PWSS)和普通的web service site(WSS). 用户通过PWSS发送请求, PWSS负责维护对应的WSS的一致性和出错处理.
(2) 不涉及WSC QoS
论文(四)
SALAS J, PEREZ-SORROSAL F, PATINO-MARTINEZ M, et.al. WS-replication: a framework for highly available web services [C]// Proceedings of the 15th international conference on World Wide Web (WWW). Edinburgh, Scotland: Association for Computing Machinery, 2006: 357 - 366
(1) 本文提出了WS-Replication架构(infrastructure), 用于WAN环境中WS的replication.
WS-Replication的目的是使WS具有高度的availability, 从而能够满足mission critical system的需求.
这个架构基于group communication WS, WS-Multicast. WS-Multicast的传输是基于SOAP, 依赖WS进行跨组织的交互.
WS-Replication中采用了active replication的方式.
这四篇论文看的都比较粗略, 只是了解了一下论文的大概工作, 没有通读全文. 读了之后, 对WS replication有以下印象:
1. 作为replica的web services一般都是同一份实现, 需要维护保证代码和状态的一致性
2. WS不是动态发现的
3. 不是在WSC的场景下讨论, 主要针对WS的可靠性, 不涉及其他QoS
4. 都是通过middleware来支持web service replication
5. 需要考虑replica的location
