August 2019
Beginner to intermediate
232 pages
3h 50m
Chinese
Content preview from Web容量规划之美
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18
第
1
章
扩展数据库驱动的网络应用在演变、成熟过程中可以选择不同的途径。一些方案
会选择联合横跨多个主数据库的数据，它们可能将数据库划分成集群，或者选择
用各种数据缓存的方式来降低数据库层的负载。而另外一些可能采用一种混合的
方式，使用所有这些扩容的方法。本书不打算成为一本关于数据库扩展的专著，
而是一个帮助你想出适合自己环境的规划和预测方法的指南。
用系统统计表呈现问题
服务器统计数据仅描述了你系统健康状态的一部分。就刻画使用情况方面来看，
服务器统计数字没有太大意义，除非它们能够联系实际的网站度量指标。这也使
你应当知道如何随时间变化跟踪容量。
例如，知道你的网站服务器每秒正处理
X
个请求是很容易的，但应了解这每秒的
X
个请求对用户意味着什么会更好。可能每秒
X
个请求代表着
Y
个用户正同时使
用该网站。
最好知道，哪些是
Y
个同时用户，
A
%
是现场直播的事件，
B
%
是上传照片
/
视频，
C
%
的人在激烈的论坛话题上发表评论，还有
D
%
的人在等待送披萨人到来的时候
随意地在网站
/
移动
App
周围乱点。随着时间的推移测量这些用户度量是第一步。
比较和绘制
Web
服务器每秒单击次数与这些用户交互度量之间的关系，最终会得
到给用户提供服务需要哪些成本。在前面的示例中，在应用程序中生成注释的能
力可能比浏览站点时消耗更多的资源，但比上传照片消耗要少。了解哪些功能比
其他功能更重要，这给了你决定规划过程中优先关注哪些方面的上下文。这些意
见也有助于推动任何技术采购的理由。一个经典的例子是在推特转发功能。某个
名人转发由于大扇出导致服务压力过大（相当于大量的追随者，截至 ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.