技术

  • AWS,  性能,  技术

    AWS back-of-envelope latency measure

    July 3, 2022 /

    Network Roundtrip latency between two instances in the same AZ: sub-millisecond Roundtrip latency between two instances in a different AZ in the same Region: single-digit millisecond Data Transformation costs money. DynamoDB is cross-region replication by default so I assume normally it won’t cost money Data in/out ALB may not cost money if they are in same VPC (not sure) Service DynamoDB: Single-digit millisecond RDS: Single-digit millisecond Redis: sub-millisecond E2E The following data come from real traffic; and since our ECS is multi-region so the data includes traffic between different AZs. EC2 to Salesforce: p95 1s p50 0.6s (upsert) EC2 to DynamoDB: p95 around 20ms p50 20ms (read&write) EC2 to RDS:…

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  • 工具,  技术

    注册欧陆词典

    July 1, 2022 /

    欧路词典真的挺好用的，Mac版本需要150多块钱。 教程如下： 文字版 1.安装任意版本的欧路词典，打开一次并退出。 2.打开Finder前往”~/Library/Preferences”找到com.eusoft.eudic.plist文件。 3.使用PlistEdit Pro打开，修改MAIN_TimesLeft中的数值为820711（试用天数）。 4.将文件锁定、改为只读。 Notes: If you don’t have PlistEdit Pro, you can use https://github.com/ic005k/Xplist/releases/tag/1.2.47 Actually even the PlistEdit Pro shows expired it seems still saved the file anyways.

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  • 技术,  网站

    After upgrading Ubuntu Workpress stopped working

    June 25, 2022 /

    The reason is php got updated to 8. Just do: apt-get install php8.0-mysql And restart your apache sudo service apache2 restart Update on Jan 21, 2023 after upgrading to Ubuntu 22.04, all php shows source code: Then showing “`Your PHP installation appears to be missing the MySQL extension which Is required by WordPress`” again:

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  • Docker,  技术

    ReadTimeout on starting docker compose

    June 16, 2022 /

    Here is the exception that I got every time I try to start my docker compose: ERROR: for webdav HTTPConnectionPool(host='192.168.103.98', port=2375): Read timed out. (read timeout=60) First thing first, it’s not a network issue. After some investigation, it turns out to be that the volume I am mapping to one of containers just not able to access: mysql: restart: unless-stopped image: "percona:5.7" ports: - "23307:3307" environment: MYSQL_ROOT_PASSWORD: "developer" MYSQL_DATABASE: "zapps_amq" MYSQL_ALLOW_EMPTY_PASSWORD: "yes" MYSQL_USER: zuora MYSQL_PASSWORD: password volumes: - /mnt/zuora/application/billing/docker/infra/mysql/conf:/etc/mysql:ro - /mnt/zuora/application/billing/docker/infra/mysql/initdb.d:/docker-entrypoint-initdb.d:rw So it seems that it timeouts when trying to mount the volume. The error message is really mis leading.

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  • Linux,  技术

    How to change default port for Apache2

    April 23, 2022 /

    This example is for Ubuntu. Run sudo apachectl -S to check which conf file you are using. The result is something like: Then update the file /etc/apache2/sites-enabled/000-default.conf. Change the default file in that file. You need to change another file /etc/apache2/ports.conf. to update it to the right port. Restart apache sudo service apache2 restart Then check the status: sudo apachectl -S Done.

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  • Linux,  技术

    How to handle storage running out of space issue in linux

    March 10, 2022 /

    If you run out of space in one disk and you want to add a new one but you would like to move the existing data to the new disk, what would you do? Step 1: Identify the big folder Identify the folder which has the biggest files and you want to move. Here is the command you may want to run: -S Do not include the size of subdirectories. This is very useful and it would exclude the parent folder if the child folder on the list already. This would save you a lot of trouble to de-dup. the two -h should use together. We list the human readable…

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