Percona 的人接受 AWS 的建議,重新測試了 Percona XtraDB Cluster 在 gp2 上的效能...

去年年底的時候 Percona 的人在 AWS 上測試 Percona XtraDB Cluster 的效能,尤其是針對底層應該選擇哪種 EBS 的部分給了一些建議。可以參考先前寫的「Percona 分析在 AWS 上跑 Percona XtraDB Cluster 的效能 (I/O bound)」這篇。

當時的建議是用 io1,雖然是比較貴,但對於效能比較好。

而後來 Percona 的人收到 AWS 工程師的建議,可以用另外一個方式,可以在 gp2 上拉出類似的效能,但成本會比 io1 低不少:「Percona XtraDB Cluster on Amazon GP2 Volumes」。

這個方式是利用 gp2 會依照空間大小,計算可用的 IOPS。在官方的文件裡是這樣描述 gp2 的效能 (IOPS):

General Purpose SSD (gp2) volumes offer cost-effective storage that is ideal for a broad range of workloads. These volumes deliver single-digit millisecond latencies and the ability to burst to 3,000 IOPS for extended periods of time. Between a minimum of 100 IOPS (at 33.33 GiB and below) and a maximum of 10,000 IOPS (at 3,334 GiB and above), baseline performance scales linearly at 3 IOPS per GiB of volume size. AWS designs gp2 volumes to deliver the provisioned performance 99% of the time. A gp2 volume can range in size from 1 GiB to 16 TiB.

在這個前提下,需要 10000 IOPS 的效能會需要 3.3TB 以上的空間,所以 Percona 就被 AWS 的工程師建議直接拉高空間重新測試:

After publishing our material, Amazon engineers pointed that we should try GP2 volumes with the size allocated to provide 10000 IOPS. If we allocated volumes with size 3.3 TiB or more, we should achieve 10000 IOPS.

首先是測出來的效能,可以看到沒有太大差異:

接下來就比較儲存成本,大約是 io1 版本的一半價錢:

如上面文件中提到的,gp1 不完全保證效能,但統計出來經常能夠提供出 3 IOPS/GB 的效能。而 io1 則是保證效能,不太需要擔心效能不穩定的問題。就是這個差異,反應到成本上面就有蠻大的差距。善用這點設計系統,應該會對整體成本有蠻大的幫助... (但對 latency 就未必了,尤其是 P99 之類的數值)

算是另外一種搞法讓大家可以考慮...

測試 TPUv2 的 C/P 值

有人用相同演算法實際測試 Google 的 TPUv2 與 NVIDIATesla P100 的 C/P 值了:「Benchmarking Google’s new TPUv2」。

如果以 ResNet-50 當作計算的演算法,可以看到其實 C/P 值的差距沒有想像中大。主要原因是 GPU 可以使用較低的精度計算以加快速度,而非 Google 之前新聞稿故意使用較高精度比較 (TPU 使用 8-bit matrix engine,所以 GPU 使用較低的 fp16 版本比較會比較有參考價值):

真正的差異是在 LSTM

It turns out that the TPU is even faster on the LSTM model (21402 examples/s): ~12.9 times faster than a P100 (1658 examples/s) and ~7.7 times faster than a V100 (2778 examples/s)!

不過這邊就沒特別提到精度了...

Steam 停止使用 Bitcoin 購買遊戲

Steam 宣佈停止使用 Bitcoin 購買遊戲:「Steam is no longer supporting Bitcoin」。

官方提到的原因是因為交易費用太高 (雖然是讓使用者付):

In the past few months we've seen an increase in the volatility in the value of Bitcoin and a significant increase in the fees to process transactions on the Bitcoin network. For example, transaction fees that are charged to the customer by the Bitcoin network have skyrocketed this year, topping out at close to $20 a transaction last week (compared to roughly $0.20 when we initially enabled Bitcoin).

另外一個原因是波動問題:

Historically, the value of Bitcoin has been volatile, but the degree of volatility has become extreme in the last few months, losing as much as 25% in value over a period of days.

所以這樣推測,Steam 不是直接換成法幣?我記得他們合作的交易所 (BitPay) 可以馬上換成法幣...

Amazon EC2 推出 T2 Unlimited,可以付費超量使用 CPU

Amazon EC2t2 系列的機器上推出 T2 Unlimited:「T2 Unlimited – Going Beyond the Burst with High Performance」。

這不是新的機種,而是現有的機器上可以超量使用 CPU credit,AWS 會另外收費。

新開的機器與已經開的機器都可以打開:

us-east-1 來算,其實相當便宜,看不出什麼 penalty fee:t2.micro 的 CPU credit 是 10% baseline,每小時單價是 $0.0116,所以先有個 100% 數字是 $0.116 的概念 (如果所有東西都是十倍)。

us-east-1 的 T2 Unlimited 是 $0.05 vCPU-hour,這樣看起來其實不賴?風險應該是在於不保證可以拿到多的 CPU resource...

可能要重新算一下 c4c5 的使用方式了...

另外雖然文章後面寫了一大串,但對照 region 表後,看起來是所有的區域都支援了:(美國政府的 region 除外)

You can launch T2 Unlimited instances today in the US East (Northern Virginia), US East (Ohio), US West (Northern California), US West (Oregon), Canada (Central), South America (São Paulo), Asia Pacific (Singapore), Asia Pacific (Sydney), Asia Pacific (Tokyo), Asia Pacific (Mumbai), Asia Pacific (Seoul), EU (Frankfurt), EU (Ireland), and EU (London) Regions today.

AWS 推出新的 Cost Explorer API,不過 API 不是重點啦...

AWS 的「New – Interactive AWS Cost Explorer API」這篇文章在一開頭就提到了 Cost Explorer API 的情況,所以他們要推出新的 API 改進:

We launched the AWS Cost Explorer a couple of years ago in order to allow you to track, allocate, and manage your AWS costs. The response to that launch, and to additions that we have made since then, has been very positive. However our customers are, as Jeff Bezos has said, “beautifully, wonderfully, dissatisfied.”

不過讓我笑出來的是選圖啊... 大概是 Jeff Barr 夠硬的關係,直接選了這張:

我喜歡這張 XD (尤其配合著出現在官方 blog 上的時候)

Amazon EC2 的 C5 家族...

Amazon EC2 推出新的 instance:「Now Available – Compute-Intensive C5 Instances for Amazon EC2」,官方宣稱這次單位價錢的效能與 C4 相比大約提升了 25%,而極端的情況可以到 50%:

The new instances offer a 25% price/performance improvement over the C4 instances, with over 50% for some workloads.

這次比較特別的是切分方式,是 large、xlarge、2xlarge、4xlarge、9xlarge (咦?) 以及 18xlarge (...)。

然後亞洲區都還沒上 XD

You can launch C5 instances today in the US East (Northern Virginia), US West (Oregon), and EU (Ireland) Regions in On-Demand and Spot form (Reserved Instances are also available), with additional Regions in the works.

有 Lazy Connection 功能的 PDO object

在「Aura.Sql」這邊看到有提供 Lazy Connection 的 PDO object,而且是繼承自本來的 PDO object:

Provides an extension to the native PDO along with a profiler and connection locator. Because ExtendedPdo is an extension of the native PDO, code already using the native PDO or typehinted to the native PDO can use ExtendedPdo without any changes.

Lazy connection. ExtendedPdo connects to the database only on method calls that require a connection. This means you can create an instance and not incur the cost of a connection if you never make a query.

之後可以拿來跟 LaravelEloquent 一起用看看。本來的 PDO 物件在建立時就會建立連線,對於連線的開銷其實蠻大的,用這個應該是個方向...

另外是 Profiler 的能力,需要用的時候應該會很好用:

Profiler. An optional query profiler is provided, along with an interface for other implementations, that logs to any PSR-3 interface.

引一下來源,當初是從「Atlas.Orm 2.0 Is Now Stable」這邊在看文件時一路看到的。

Amazon RDS 的 RI 也支援彈性計價了

AWS 宣佈 RDS 的 RI 也支援彈性計價了:「Amazon RDS Reserved Instances Offer Instance Size Flexibility」。

也就是說跟 EC2 的 RI 方式切齊,買 db.m4.2xlarge 的 RI 後,可以用在兩台 db.m4.xlarge 上:

For example, let’s say you purchased a db.m4.2xlarge MySQL RI in US East (N. Virginia). The discounted rate of this RI can automatically apply to 2 db.m4.xlarge MySQL instances without you needing to do anything.

包括了相當多種類的 RDS,主要是沒有 license fee 的類型都包括在內了:

Amazon RDS Reserved Instance size flexibility is offered in all regions for the MySQL, MariaDB, PostgreSQL, and Amazon Aurora database engines, as well as the “bring your own license” (BYOL) edition of the Oracle database engine. To learn more about flexible RIs, please visit the Amazon RDS Reserved Instances Page.

但不包括要另外收 license fee 的 SQL Server 與 Oracle LI edition:

Size flexibility does not apply to Microsoft SQL Server and the License Included (LI) edition of Oracle.

用 Xbox 控制器操控潛艇

拿民用品當作軍事器材不是第一次了,不過拿來操作潛艇倒是蠻值得看一下的:「The U.S. Navy's most advanced submarines will soon be using Xbox controllers」。


在 lab 環境測試的畫面。

原因頗簡單,就是成本考量,而且很容易取得:

The company says the photonic mast handgrip and imaging control panel that cost about $38,000 can be replaced with an Xbox controller that typically costs less than $30.

不過有個問題啊,軍用品一般都可以抵抗 EMP,這種民用品應該不行吧 XDDD

透過 AWS Budgets 管控 Reserved Instance 的使用率

現在可以透過 AWS Budgets 來看到 Reserved Instance 的使用率了:「Monitor your Reserved Instance utilization by receiving alerts via AWS Budgets」。

Starting today, customers can now monitor and receive alerts when their Reserved Instance (“RI”) utilization falls below the threshold they define.

算是個開頭,不過我更想請 AWS 分析有哪些機器是長年開著沒有 discount 的... 或者像是 GCP 那樣自動算 :o