A brand new Rails/Merb app you put together over a weekend, a pack of Mongrels, a reverse proxy (like Nginx), and you're up and running. Well, almost, what about that one request that tends to run forever, often forcing the user to double check their internet connection? Response time is king, and you always want to make sure that your site feel snappy to the user. Did you know that Flickr optimizes all of their pages to render in sub 250ms?
When you're fighting with response times, the worst thing you can possibly do is queue up another request behind an already long running process. Not only does the first request take forever, but everyone else must wait in line for it to finish as well! To mitigate the problem HAProxy goes beyond a simple round-robin scheduler, and implements a very handy feature: intelligent request queuing!
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更多http://www.igvita.com/2008/05/13/load-balancing-qos-with-haproxy/
故障现象
在数据库帐号密码没有问题，但应用死活连不上MSSQL数据库，日志报校验错误。
处理步骤
1、更换了MS官方的驱动换成开源的jtds-1.2.jar包问题依旧。
2、写了一个简单的jsp测试文件能正常连接数据库，晕。可以确定帐号、密码、MSSQL服务没有问题。
3、查看连接池配置，发现密码域串含有"&"号，在XML中是属于转义符，更个密码，连接成功：）
注：在XML中“&”号需要转成“&；”
在数据库帐号密码没有问题，但应用死活连不上MSSQL数据库，日志报校验错误。
处理步骤
1、更换了MS官方的驱动换成开源的jtds-1.2.jar包问题依旧。
2、写了一个简单的jsp测试文件能正常连接数据库，晕。可以确定帐号、密码、MSSQL服务没有问题。
3、查看连接池配置，发现密码域串含有"&"号，在XML中是属于转义符，更个密码，连接成功：）
注：在XML中“&”号需要转成“&；”
