August 2019
Beginner to intermediate
232 pages
3h 50m
Chinese
Content preview from Web容量规划之美
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98
第
3
章
图
3
-
17
：Squid 请求率和 CPU 负载（用户和系统）的五个月视图
图
3
-
18
：Squid 服务器磁盘 I/O 等待和使用率的五个月视图
99
测量
：
容量的单位
图
3
-
19
：Squid 请求率与磁盘 I/O 等待：每日视图
既然我们有了自己的相关性，让我们在
Excel
中对数据按递增方式排序并重新绘制。
如图
3-20
所示，这可以使我们更容易发现在某一特定时刻，数据请求量相关的趋势。
现在，我们可以清楚地看到两个度量指标上升时如何互相关联，以及磁盘
I/O
等待
如何影响
Squid
的性能。
图
3
-
20
：Squid 请求率与磁盘 I/O 等待：递增视图
Squid
保存处理缓存命中或错过的时间方面的内部度量指标。我们也可以通过
Ganglia
收集这些指标。我们不太关心缓存未命中的时间，因为在很大程度上，这
100
第
3
章
并不能告诉我们高速缓存处理的上限，未命中大部分是因为网络和源服务器的紧
张。命中来自
Squid
内存和磁盘缓存，所以那才是我们想要集中注意的地方。图
3-21
给出了五个月的结果。
图
3
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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.
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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.