聚沙成塔-小哈的记事薄

昨天百度上了电视新闻，我权当看热闹，今天轮到了谷歌，这下我坐不住了。

一篇《A New Approach to China》掀起了今天的轩然大波，我订阅的RSS里，有关互联网的博客几乎都讲了这件事。

英文够好瞧这里 Google Just Says No to China

国内的文章我觉得这篇最详细，分析最透彻 宁为玉碎，不为瓦全

怎么说呢，如果google真退出中国，一并带走全部的产品，那我们IT行业就只剩下半条命了。遇到一般问题，开发人员还好，工作台上放几本工具书，有需要了就翻翻，但像我外勤的有时候记不起一个命令如何使用那只得靠google。

如果不是差个工具书就能解决的问题，而需要troubleshooting的话，那更得靠google。你琢磨破脑袋的问题，也许别人刚遇到过还写下来了，大家都琢磨不透的问题你一搜原来官方放出了补丁。google.cn搜不了了，那就换google.com，中文的有问没答那就换英文关键字。

没了google，你说用百度么？百度只适合娱乐、八卦和广告，有点深度的技术内容它是找不到的，找到的也是一篇篇白莲山的转载、垃圾网站的采集。

有人说这不过是google试探的手法，它也没正式宣布，只是在一个博客上放个风声，中国的市场它放弃不了的。我也希望如此，真怕它向我们展示一个有社会责任意识的公司会做的那样（今天google.cn的搜索结果就有些不老实了）。google真退出中国，对于90%的中国人应该是日子照过，但是对于我来说，那将是黑暗日子的开始。

居然两周没在这里更新，主要最近研究“三国杀”比较多，乱七八糟想的比较多。

新的一年要多读书，技术的和非技术的。过两天能拗到一本百来块的记事簿，就来写读书笔记好了。

交大的在职研究生应该没问题了，但是由于从事的工作不需要编程，要重新写起代码恐怕还需要努力一把。

一年年过的真是很快，真怕几年后看到自己还是原地踏步。在余晟的博客看到这么一段话，十分有感触。

每天花10分钟写日记，“想写什么就写什么，重要的是坚持，第一点要克服的障碍就是‘不想写’”。一年下来，记下了厚厚的一本：终于从信马由缰、恣意而为，到规律、精炼起来。更重要的是，通过持续的记述来感知和反思，加深对自己的认识；这有点像从各个不同的方向来照镜子，于是慢慢能认清自己的形象。

Mina Fighting!

Tools and Tips to Diagnose Performance Issues

分析性能问题的一些工具和建议

好东西，赶紧拉下来，介绍的太完整了，从内存调整到各种池大小优化。developerworks上都难得一见的完整调优案例。

原文链接：http://www.ibm.com/developerworks/cn/websphere/techjournal/0909_blythe/0909_blythe.html

IBM WebSphere Application Server 是一种可靠的企业级应用服务器，它提供了一组核心组件、资源和服务，供开发人员在应用程序中使用。每个应用程序都具备特有的需求，并且经常采用截然不同的方式使用应用服务器的资源。为了提供高度灵活性并支持这种广泛的应用程序，WebSphere Application Server 提供了一组全面的参数来帮助您增强对应用程序的调优。

应用服务器已经为最常用的调优参数设置了默认值，以确保能为最广泛的应用程序提供开箱即用的性能改善。但是，由于任意两个应用程序都不可能采用完全相同的方式来使用应用服务器，因此无法确保一组调优参数能适用于所有应用程序。这也突显了对应用程序执行有重点的性能测试和调优的重要性。

本文将讨论在 WebSphere Application Server V7.0（和之前发行版）中最常使用的一些参数，以及对它们进行调优的方法。与其他相关文章提供的调优建议不同，本文将使用 Apache DayTrader Performance Benchmark Sample 案例研究作为本文的上下文。借助 DayTrader 应用程序，您可以清楚地确定所使用的主要服务器组件，对这些区域进行重点调优，并观察各种调优更改所带来的收益。

在继续阅读之前，需要记住关于应用服务器性能调优的一些事项：

• 提高性能经常会牺牲应用程序或应用服务器的一些特性或功能。在计算性能调优更改时应该仔细考虑性能和特性之间的权衡。
• 应用服务器之外的一些因素有时会影响性能，包括硬件和操作系统配置、系统中运行的进程、后端数据库资源的性能、网络延迟等等。您在自己执行性能评估时，必须将这些因素考虑在内。
• 此处讨论的性能改善仅针对 DayTrader 应用程序，并且特定于此处描述的工作负载组成及所支持的硬件和软件栈。您通过本文介绍的调优更改实现的应用程序性能提升肯定会有所不同，并且应该通过您自己的性能测试进行评估。

阅读全文…

如果你想订阅这个邮件列表，发送邮件到wsehelp@us.ibm.com即可，邮件名称标注“subscribe WebSphere Application Server”

WebSphere Application Server Customer,
As a valued WebSphere Application Server customer who has contacted technical support, we are hoping you will find this information useful.
This note contains links to WebSphere Application Server technical support documents and information that can help you obtain value from your software. It is intended to help you to be proactive in your support and administration of WebSphere Application Server.

• • • Learn more about the portal
    • View the demo videos
    • Access the IBM Support Portal and sign in with your IBM ID and password

  1. Don’t be caught by surprise – try the IBM Support Portal today
  On January 6 the new IBM Support Portal, a unified, centralized view of all technical support tools and information for all IBM software, replaces the existing software product support pages. You can tailor the Support Portal to suit your needs, focusing on the software and hardware products you care about and organizing the pages to reflect the way you work. The portal makes it fast and easy to find the information or tools you need to prevent and resolve problems.We hope you can take a few minutes to fill out a short questionnaire that evaluates the IBM Support Portal in comparison to the existing IBM support website pages. We appreciate your feedback!
  2. IBM WebSphere Application Server Migration Toolkit
  The IBM WebSphere Application Server Migration Toolkit helps organizations migrate applications from other application servers to IBM WebSphere Application Server. WebSphere Application Server, a Java EE 5 certified, EJB 3.0 supported technology-based application platform, is a key part of the IBM Smart SOA Application Foundation that delivers the innovation and performance essential to cost-effectively build, deploy and manage robust SOA applications.
  http://www.ibm.com/developerworks/websphere/downloads/migration_toolkit.html
  3. developerWorks: WebSphere Application Server security
  This page of essential resources contains hints, tips, and valuable guidance to help you configure and use WebSphere Application Server security more effectively, and to design and develop your WebSphere Application Server solutions in ways that will make them more secure. Also included is information on the security environment in which WebSphere Application Server resides.
  http://www.ibm.com/developerworks/websphere/zones/was/security/
  4. Follow WebSphere Support on Twitter
  A list of available Twitter accounts for WebSphere Support.
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg21410956
  5. WebSphere Application Server Feature Pack for XML
  The IBM WebSphere Application Server V7 Feature Pack for XML delivers updated XML programming model standards to help improve developer productivity and address new application development scenarios.
  http://www.ibm.com/software/webservers/appserv/was/featurepacks/xml/
  6. IBM Support Assistant – helping you simplify support
  If you haven’t tried the IBM Support Assistant yet, use the Quick Start Guide to find out what you’re missing! Save time with automated collectors and over 20 robust problem determination tools. IBM Support Assistant can be customized for over 350 IBM software products. The ISA Lite offering lets you quickly use the accurate, automated data collection capability. Download the workbench or ISA Lite to simplify support and save time. Not sure which one you need? Use the handy chart on the page to help you decide.
  7. The Support Authority: Know what your Web application is really doing
  The IBM Monitoring and Diagnostic Tools for Java – Health Center is a lightweight tool that monitors IBM virtual machines for Java with minimal performance overhead. It provides live information and recommendations about classes being loaded, the virtual machine environment, garbage collection, locking, and profiling. This article introduces you to the Health Center and shows an example of how it can be used to check the impact of a source code change in a Web application.
  http://www.ibm.com/developerworks/websphere/techjournal/0911_supauth/0911_supauth.html
  8. The Support Authority: Analyze memory management problems with the Memory Dump Diagnostic for Java (MDD4J)
  The Memory Dump Diagnostic for Java (MDD4J) tool helps you diagnose memory leaks and other excessive memory consumption problems in applications running in IBM Java Virtual Machines (JVMs). This article introduces you to MDD4J and shows you how to use its sophisticated analysis engine and user interface to peer into the Java heap so you can see which objects are consuming the most amount of memory.
  http://www.ibm.com/developerworks/websphere/techjournal/0909_supauth/0909_supauth.html
  9. One plug-in config to handle multiple Portal Applications in multiple Portal Clusters
  I have different Portal applications running in 2 different Portal Clusters. I want to use only 1 IBM HTTP Server Web server to route requests correctly for both applications in both clusters. How can I configure the Web server plug-in to accomplish this?
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg21397408
  10. Web server plug-in routing to SAME application in DIFFERENT clusters
  If I install the same Web application into more than one WebSphere Application Server cluster, is it possible to configure the Web server plug-in to properly route requests to the application in both clusters?
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg21331062
  11. IBM Service Integration Bus Destination Handler, Version 1.1
  A tool to view, move, copy, delete, save and restore messages in the default messaging provider for IBM WebSphere Application Server versions 7.0, 6.1, and 6.0.
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg24021439
  12. Solution for installing 32-bit Java SDK fix packs on IBM HTTP Server V7.0 using Update Installer 7.0.0.5 and earlier
  For most operating systems and architectures, you should install the 32-bit Java SDK fix packs for IBM HTTP Server V7.0, even if that IBM HTTP Server was installed from the 64-bit Supplemental installation image. However, due to a defect in the process, Update Installer V7.0.0.5 and earlier will not allow you to install the 32-bit Java SDK fix pack, and will erroneously allow you to install the 64-bit Java SDK fix pack instead. This technote explains how to address this problem.
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg21395882

  1. End of Support – WebSphere Application Server V5.1
  WebSphere Application Server V5.1 content has been “EOSed”. IBM ended the support for IBM WebSphere Application Server version 5.1 products in September 2008. WebSphere Application Server V5.1 content, including product documentation, technotes, Fix Packs and Interim Fixes, is now available from the WebSphere End of Support Products Web site.
  http://www.ibm.com/support/docview.wss?rs=3680&uid=swg21410048
  2. Recommended fixes for WebSphere Application server
  A comprehensive list of recommended, generally available (GA) fixes for IBM WebSphere Application Server releases.
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  3. Fixes by version for WebSphere Application Server
  A comprehensive list of generally available (GA) fixes for WebSphere Application Server releases.
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27006899
  4. Feature packs by version for WebSphere Application Server
  A comprehensive list of generally available (GA) feature packs for WebSphere Application Server
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27008534
  5. Detailed system requirements for WebSphere Application Server
  Identifies the supported software options by operating system for the WebSphere Application Server product.
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27006921
  1. WebSphere Application Server Administration Using Jython
  Utilizing Jython scripting, you can dramatically reduce the effort, resources, and expense associated with managing WebSphere Application Server. WebSphere Application Server Administration Using Jython will show you how. The first start-to-finish guide to Jython scripting for WebSphere administration, this book’s practical techniques and downloadable scripts can help you improve efficiency, repeatability, and automation in any WebSphere environment.
  *Using coupon code IBM9527 provides you a 35% discount AND Free Shipping!
  http://www.ibmpressbooks.com/bookstore/product.asp?isbn=0137009526
  2. Join us for these Electronic Support webcasts
  During the month of January, the Global WebSphere Community will offer a series of four electronic support webcasts. Check the web site for details on joining the webcasts:
  January 7 webcast – “It’s official – the IBM Support Portal is here!”
  January 14 webcast – “Quick guide to electronic support and a close look at the Service Request tool”
  January 21 webcast – “Discover IBM Support Assistant – ready to help when you need it”
  January 28 webcast – “IBM portfolio of troubleshooting tools: helping you solve problems faster”
  3. IBM WebSphere Application Server V7.0 Web Services Guide
  This IBM Redbooks publication describes how to implement Web services in IBM WebSphere Application Server V7. It starts by describing the concepts of the major building blocks on which Web services rely and leading practices for Web services applications.
  http://www.redbooks.ibm.com/abstracts/SG247758.html
  4. Technical Exchange Webcasts
  Take full advantage of your product. Join us as technical experts share their knowledge and then answer your questions. Visit this site often to see upcoming topics.
  http://www.ibm.com/software/websphere/support/supp_tech.html
  5. Self-Assist Resources and Tools
  Find out how online software support tools and resources can save you time, keep you informed, provide training, and help streamline your support experience!
  http://www.ibm.com/software/websphere/support/d2w.html
  6. developerWorks WebSphere Application Server zone
  Access the developerWorks page for downloads, learning resources and more.
  http://www.ibm.com/developerworks/websphere/zones/was/

In the spotlightPlan

Education

Kind regards,
The WebSphere Application Server team.

现在的服务器性能越来越强，内存动辄4G、8G，而32位JDK下，单个java堆一般不超过1.7G。那多出来的内存怎么办？建垂直集群（Vertical clusters：垂直集群是指同一机器上部署多个服务器，充分利用硬件资源）可以，简单的部署多个appserver也行。但是应用如何处理？如果多个项目都需要用相同的context root，比如说/，那怎么办？

其实做过网站的朋友都知道，一台服务器上一般不可能只放一个网站，那如何访问到这些网站，有三种方法：

1. IP不同，一个网卡上绑定多个IP，不同的IP对应不同的网站。
2. 端口不同，不同的网站运行在不同的端口上。
3. 虚拟主机不同，通过不同的虚拟主机名（一般都是域名）来访问。

那对于webshpere或者weblogic，很明显可以实行的是上述第三种方案。部署应用时会让我们选择部署到哪台虚拟主机，默认的都为default host，所以我们只要新建一个虚拟主机，名称一般为域名。那么就能实现通过一级域名直接访问应用。即使一台app server上部署了多个应用。

这种设置对于提供互联网服务的应用尤其有效，因为大家本来就是通过域名来访问的。而且即使只有一个应用，设置非默认的虚拟主机名可以起到只能通过域名来访问，而IP地址访问则会得到应用服务找到的错。虽说提高的安全性不多，但能满足年底全市各部门关于“只能通过域名访问，而IP无法访问”的要求。

至于内网用户，可以在内部dns上配置域名解析，或者编写hosts文件，达到同样效果。

更新：对于webshpere，我测试下来即使不同的虚拟主机，相同的上下文根也无法同时启动。在日志里会看到已经有重复的Context root了，这样的话只能配置apache使用它的虚拟主机解决