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MDD
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.. include:: ../tags.ref
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============ ==========================
**Abstract** Metrics Driven Developement
**Category** learning note
**Authors**  Walter Fan
**Status**   WIP as draft
**Updated**  |date|
============ ==========================

.. contents::
   :local:

Ovewview
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无法度量，就无法有效地管理，证明和提高

* If you can't measure it, you can't manage it
* If you can't measure it, you can't prove it
* If you can't measure it, you can't improve it

究竟要度量度量什么
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1. Measure your work

  - Workload, progress, efficiency, etc. 

2. Measure your production

  - Health, usage, trend, KPI, etc. 

3. Measure user's behavior

  - DAU, JMT, etc.

度量的范围
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1. Whole development lifetime 全过程

  - Design, coding, testing, deploy, etc. 

2. Whole team 整个团队

  - PM, developer, QA, Operator, etc.

3. Whole levels 全部层次

  - Infrastructure, Platform, Application, Business

度量的层次
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* 基础设施层 Infrastructure/System metrics
* 中间件层 Middleware metrics
* 应用层 Application metrics
* 业务层 Business metrics

.. image:: metrics.png

度量的内容
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* Latency 耗时
* Usage 用量
* Errors 错误
* Saturation 饱和度，例如 CPU, Memory 及 Disk 的使用及剩余量