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Microsoft SQL Server 可以跑在 t2.large 與 t2.xlarge 了...

AWS 宣佈 Microsoft SQL Server 可以跑在 t2 系列的機器上了:「Amazon EC2 T2 instance types are now supported on Windows with SQL Server Enterprise」。

不過應該是因為記憶體限制,目前只開放 t2.xlarge (8GB RAM) 與 t2.2xlarge (16GB RAM) 上可以跑:

Windows with SQL Server Enterprise Edition is now available on t2.xlarge and t2.2xlarge instance types.

馬上可以想到的是測試環境,另外就是某些不能關機的內部系統,可以用離峰時間累積 CPU credit 之類的應用?

nginx 的 HTTP/2 要支援 Server Push 了

Twitter 上看到 nginx 的 HTTP/2 也要支援 server push 的消息了:

看起來是只要送出對應的 HTTP Header,後續 nginx 就會幫你處理...

這功能總算是要進 nginx 了... 像是透過 cookie 判斷使用者是第一次瀏覽,就透過 server push 預先把 css/js 丟出去,加速頁面呈現。

Percona Server 引入 MyRocks

看到「MyRocks Engine: Things to Know Before You Start」這篇,才發現原來一月的時候 Percona Server 就已經將 MyRocks GA (General Availability) 了:「Percona Server for MySQL 5.7.20-19 Is Now Available」。

New Features:
Now MyRocks Storage Engine has General Availability status.

在二月這篇文章裡面有提到一些重點,像是安裝方式:

Now if you use Percona repositories, you can simply install MyRocks plugin and enable it with ps-admin --enable-rocksdb.

另外文章裡也提到了重要的差異 (在「What other differences should you be aware of?」這段),像是他並不是每個 table 都一個檔案,而是像早期 InnoDB 的作法,整個一包:

Let’s look at the directory layout. Right now, all tables and all databases are stored in a hidden .rocksdb directory inside mysqldir. The name and location can be changed, but still all tables from all databases are stored in just a series of .sst files. There is no per-table / per-database separation.

另外提到可以看到 Engine 的代碼是 ROCKSDB (從 ENGINE=ROCKSDB 那段看到的)。然後是 Isolation level 的支援度,只有 READ-COMMITTEDSERIALIZABLE,沒有 REPEATABLE-READ

Keep in mind that at this time MyRocks supports only READ-COMMITTED and SERIALIZABLE isolation levels. There is no REPEATABLE-READ isolation level and no gap locking like in InnoDB. In theory, RocksDB should support SNAPSHOT isolation level. However, there is no notion of SNAPSHOT isolation in MySQL so we have not implemented the special syntax to support this level. Please let us know if you would be interested in this.

然後 bulk load 在資料量超過記憶體大小時會有已知的 crash 問題:

For bulk loads, you may face problems trying to load large amounts of data into MyRocks (and unfortunately this might be the very first operation when you start playing with MyRocks as you try to LOAD DATA, INSERT INTO myrocks_table SELECT * FROM innodb_table or ALTER TABLE innodb_table ENGINE=ROCKSDB). If your table is big enough and you do not have enough memory, RocksDB crashes. As a workaround, you should set rocksdb_bulk_load=1 for the session where you load data.

然後目前沒有像 XtraBackup 的工具可以用,現階段如果要備份的話得透過傳統的方式來做 (mysqldump 或是 filesystem snapshot):

Right now there is no hot backup software like Percona XtraBackup to perform a hot backup of MyRocks tables (we are looking into this). At this time you can use mysqldump for logical backups, or use filesystem-level snapshots like LVM or ZFS.

想來找機會測試看看兩者差異...

將找 Origin Server IP 位置自動化的 CloudFlair

Twitter 上看到 CloudFlair 這個工具,可以找被 Cloudflare 保護的網站,將尋找後面 Origin Server 的 IP address 的過程自動化:

這隻程式配合 Censys 的資料去找,而不是自己獨立掃整個 IPv4 address。

另外這隻程式也不保證掃的出來,像是透過 Cloudflare 去年十一月推出的新服務 Wrap,就不需要將 Port 80/443 對 Internet 公開 (參考「Cloudflare 推出的 Wrap 讓你不用在本地端開對外的 Port 80/443」)。

不過還是蠻好玩的工具啦 XDDD

ExpressVPN 在土耳其的 VPN server 被抄...

ExpressVPN 在土耳其的 VPN server 被抄,為了調查大使的刺殺案件:「VPN Server Seized to Investigate Russian Ambassador’s Assassination」。

A VPN server operated by ExpressVPN was seized by Turkish authorities to investigate the assassination of Andrei Karlov, the Russian Ambassador to Turkey. Authorities hoped to find more information on people who removed digital traces of the assassin, but the server in question held no logs.

ExpressVPN 官方的回覆在「ExpressVPN statement on Andrey Karlov investigation」,主要的部份是:

As we stated to Turkish authorities in January 2017, ExpressVPN does not and has never possessed any customer connection logs that would enable us to know which customer was using the specific IPs cited by the investigators. Furthermore, we were unable to see which customers accessed Gmail or Facebook during the time in question, as we do not keep activity logs. We believe that the investigators’ seizure and inspection of the VPN server in question confirmed these points.

至於是不是真的,就需要時間確認了...

原來 Oracle 與 Microsoft 裡的條款是這樣來的...

看到「That time Larry Ellison allegedly tried to have a professor fired for benchmarking Oracle」這篇文章的講古,想起很久前就有聽過 Microsoft 有這樣的條款 (禁止未經原廠同意公開 benchmark 結果),原來是 Oracle 在三十幾年前創出來的?而且這種條款還有專有名詞「DeWitt Clauses」,出自當初被搞的教授 David DeWitt...

Microsoft 的條款是這樣:

You may not disclose the results of any benchmark test … without Microsoft’s prior written approval

Oracle 的則是:

You may not disclose results of any Program benchmark tests without Oracle’s prior consent

IBM 的反而在 license 裡面直接允許:

Licensee may disclose the results of any benchmark test of the Program or its subcomponents to any third party provided that Licensee (A) publicly discloses the complete methodology used in the benchmark test (for example, hardware and software setup, installation procedure and configuration files), (B) performs Licensee’s benchmark testing running the Program in its Specified Operating Environment using the latest applicable updates, patches and fixes available for the Program from IBM or third parties that provide IBM products (“Third Parties”), and © follows any and all performance tuning and “best practices” guidance available in the Program’s documentation and on IBM’s support web sites for the Program…

AWS 提供 Windows 上的 Deep Learning AMI

有一些 Windows 上的東西就可以直接開起來跑了:「Announcing New AWS Deep Learning AMI for Microsoft Windows」。

目前支援 2012 R2 與 2016:

Amazon Web Services now offers an AWS Deep Learning AMI for Microsoft Windows Server 2012 R2 and 2016.

然後 driver 與常用的東西都包進去了:

The AMIs also include popular deep learning frameworks such as Apache MXNet, Caffe and Tensorflow, as well as packages that enable easy integration with AWS, including launch configuration tools and many popular AWS libraries and tools. The AMIs come prepackaged with Nvidia CUDA 9, cuDNN 7, and Nvidia 385.54 drivers, and contain the Anaconda platform (supports Python versions 2.7 and 3.5).

AWS 環境裡面提供 NTP Service 了 (Amazon Time Sync Service)

以前在 AWS 環境裡都要自己架設兩台可以連外的 NTP server,然後將內部機器指到這兩台上,現在可以用現成的了:「Keeping Time With Amazon Time Sync Service」。

服務放在 169.254.169.123

You can access the service via the link local 169.254.169.123 IP address. This means you don’t need to configure external internet access and the service can be securely accessed from within your private subnets.

然後也有提到 leap second 的解法,用的解法是 leap smearing:

Leap seconds are known to cause application errors and this can be a concern for many savvy developers and systems administrators. The 169.254.169.123 clock smooths out leap seconds some period of time (commonly called leap smearing) which makes it easy for your applications to deal with leap seconds.

先前 AWS 也有 leap time,但不包括 Amazon EC2 這些系統 (EC2 裡的時間是獨立的),不過還是可以看一下 AWS 處理 leap time 的方式,因為這次 NTP Service 就會拿去用了。

最近一次 leap time 是 2016 年底的「Look Before You Leap – December 31, 2016 Leap Second on AWS」,處理的方式跟 2015 年時的方法還是一樣:「Look Before You Leap – The Coming Leap Second and AWS (Updated)」。

類似於下圖左上角這張的變化:

然後全區開放,都可以用了:

This service is provided at no additional charge and is immediately available in all public AWS regions to all instances running in a VPC.

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