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阿里靠什么武功秘籍渡过“双十一“的天量冲击

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双十一大概会产生多大的数据量呢,可能大家没概念,举个例子央视拍了这么多年电视新闻节目,几十年下来他存了大概80P的数据。而今年双11一天,阿里要处理970P的数据,做为一个IT人,笔者认为今年”双十一“阿里最大的技术看点有有以下两个:

阿里的数据库,也就是刚刚拿下TPC冠军的OcceanBase,处理峰值也达到了骇人听闻的6100万次/秒,
阿里核心系统百分百上云了。
如果把信息系统比做一个武林高手,那么如此之大的交易量代表了他的刚猛威武,而全面触云又代表他灵动飘逸。而能把刚猛和灵活完美结合是简直是神才能达到的境界。

上云虽好,但不适合大规模计算,由于底层与用户之间多了一个虚拟化层,所以云计算平台一般都会产生10%左右的调度损耗,而这10%的损耗也让很多密集计算型的应用场景不太合适使用云平台。所以站在IT视角,云计算也不太合适双十一的场景。那么阿里刚猛兼顾灵活的武功是如何练成的呢?

乾坤大挪移-Tair

通过阿里的官宣来看在Tair之前还有一个LVS的负载均衡层,不过那些都不是国产的自研技术,也不细表了。

Tair是阿里自研的开源缓存服务中间件(Github地址:。https://github.com/alibaba/tair)提供快速访问的内存(MDB引擎)/持久化(LDB引擎)存储服务,基于高性能、高可用的分布式集群架构,满足读写性能要求高及容量可弹性伸缩的业务需求,在双十一秒杀的体系内完成乾坤大挪移般的加速工作。

通常情况下,一个 Tair 集群中包含2台 Configserver 及多台 DataServer。其中两台 Configserver 互为主备。通过和 Dataserver 之间的心跳检测获取集群中存活可用的 Dataserver,构建数据在集群中的分布信息。Dataserver 负责数据的存储,并按照 Configserver 的指示完成数据的复制和迁移工作。Client 在启动的时候,从 Configserver 获取数据分布信息,根据数据分布信息,和相应的 Dataserver 进行交互,完成用户的请求。

其核心的模块就是Configserver,具体的代码在https://github.com/alibaba/tair/blob/master/src/configserver/conf_server_table_manager.cpp

以初始化函数为例:

using namespace std;

void conf_server_table_manager::init()

{ …

How to remove all formula references but keep values in cells in Excel?

  1. Select the cells you need to remove all references, then press Ctrl + C keys, keep these cells selected, right click and select Values under Paste Options section.
  2. Then you can see all formula references of selected cells are

Get the NumSuffix(English)

Function OrdinalSuffix(ByVal Num As Long) As String
Dim n As Long
Const cSfx = “stndrdthththththth” ‘ 2 char suffixes
n = Num Mod 100
If ((Abs(n) = 10) And (Abs(n) <= 19)) _ Or ((Abs(n) Mod 10) = 0) Then OrdinalSuffix = "th" Else OrdinalSuffix = Mid(cSfx, _ ((Abs(n) Mod 10) * 2) - 1, 2) End If End Function Function NumSuffix(MyNum As Variant) As String '******************************************* 'Purpose: Add suffix to a number 'Inputs: ? NumSuffix(234) 'Output: 234th '******************************************* Dim n As Integer Dim x As Integer Dim strSuf As String n = Right(MyNum, 2) x = n Mod 10 strSuf = Switch(n <> 11 And x = 1, “st”, n 12 And x …

Good Android Widget – Small Calendar

Like the title. …

English Learn on 4/10/2010 – 5(The Gerund-)

Grammar:

Function of Gerund
1)as the subject of the sentence

    Preserving our cultural heritage is of utmost importance. Likewise, it is most important to hand down our traditional values from generation to generation.

2)after certain verbs

    Mind,enjoy,give up, avoid, …

English Learn on 3/10/2010 – 4(The Infinitive – 4)

Grammar:

Independent infinitive
    To be honest/frank

        “How do you like this condo?” ” To be honest, it leaves a lot to be desired. The price is relatively high. And what’s more, it’s badly located”

    To tell you the truth

        “Do …

English Learn on 2/10/2010 – 3(The Infinitive – 3)

Grammar:

As adverb – Function of  THE INFINITIVE
    1)for purpose

    He worked hard in order to win the prize.

The man in black stopped to light a cigarette, pondered for a second, then turned around and began to trot in …

English Learn on 1/10/2010 – 2(The Infinitive – 2)

Grammar:

As adjective – Function of  THE INFINITIVE
    1)noun + to V
    Apparently, the border incident was intended to coincide with the festival to celebrate the second anniversary of our independence.

    2)first, second, last + noun + to V

    Tiger …

English Learn on 30/9/2010 – 1(The Infinitive – 1)

Grammer:
  As nouns or pronouns – Function of  THE INFINITIVE
 1)S + V + to V
    What with one thing and another, I forgot to meet my girlfriend.
    Remember to go over your exercise for spelling errors before you hand …