loftwah

What to Expect and Tips

• 45-minute systems interview, focus on responding to real world problems with an unhealthy service, such as a web server or database. The interview will start off at a high level troubleshooting a likely scenario, dig deeper to find the cause and some possible solutions for it. The goal is to probe your knowledge of systems at scale and under load, so keep in mind the challenges of the Facebook environment.
• Focus on things such as tooling, memory management and unix process lifecycle.

Systems

More specifically, linux troubleshooting and debugging. Understanding things like memory, io, cpu, shell, memory etc. would be pretty helpful. Knowing how to actually write a unix shell would also be a good idea. What tools might you use to debug something? On another note, this interview will likely push your boundaries of what you know (and how to implement it).

Design/Architecture 

Interview is all about taking an ambiguous question of how you might build a system and letting

loftwah

Docker on Android 🐋📱

Edit 🎉

All packages, except for Tini have been added to termux-root. To install them, simply pkg install root-repo && pkg install docker. This will install the whole docker suite, left only Tini to be compiled manually.

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Summary

loftwah

How to setup a practically free CDN

I've been using [Backblaze][bbz] for a while now as my online backup service. I have used a few others in the past. None were particularly satisfactory until Backblaze came along.

It was - still is - keenly priced at a flat $5 (£4) per month for unlimited backup (I've currently got just under half a terabyte backed-up). It has a fast, reliable client. The company itself is [transparent about their operations][trans] and [generous with their knowledge sharing][blog]. To me, this says they understand their customers well. I've never had reliability problems and everything about the outfit exudes a sense of simple, quick, solid quality. The service has even saved the day on a couple of occasions where I've lost files.

Safe to say, I'm a happy customer. If you're not already using Backblaze, [I highly recommend you do][recommend].

Taking on the big boys with B2

loftwah

How we incorporate next and cloudfront (2018-04-21)

Feel free to contact me at robert.balicki@gmail.com or tweet at me @statisticsftw

This is a rough outline of how we utilize next.js and S3/Cloudfront. Hope it helps!

It assumes some knowledge of AWS.

Goals

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Adjusting child processes for PHP-FPM (Nginx)

When setting these options consider the following:

• How long is your average request?
• What is the maximum number of simultaneous visitors the site(s) get?
• How much memory on average does each child process consume?

Determine if the max_children limit has been reached.

• sudo grep max_children /var/log/php?.?-fpm.log.1 /var/log/php?.?-fpm.log

loftwah

S3 Static Sites

What this will cover

• Host a static website at S3
• Redirect www.website.com to website.com
• Website can be an SPA (requiring all requests to return index.html)
• Free AWS SSL certs
• Deployment with CDN invalidation

Resources

loftwah

#!/bin/bash
#==============================================================================
#TITLE:            mysql_backup.sh
#DESCRIPTION:      script for automating the daily mysql backups on development computer
#AUTHOR:           tleish
#DATE:             2013-12-20
#VERSION:          0.4
#USAGE:            ./mysql_backup.sh
#CRON:
  # example cron for daily db backup @ 9:15 am

loftwah

slow

This bash script offers quick shortcuts to simulate slower network connections. It is useful when you need to simulate a wireless network on a Linux network server, especially when you are using a virtual machine guest on your local machine or in the cloud.

slow 3G                   # Slow network on default eth0 down to 3G wireless speeds
slow reset                # Reset connection for default eth0 to normal
slow vsat --latency=500ms # Simulate satellite internet  with a high latency
slow dsl -b 1mbps         # Simulate DSL with a slower speed than the default

slow modem-56k -d eth0 # Simulate a 56k modem on the eth1 device. eth0 is unchanged.

loftwah

Backup android app, data included, no root needed, with adb

adb is the Android CLI tool with which you can interact with your android device, from your PC

You must enable developer mode (tap 7 times on the build version in parameters) and install adb on your PC.

Fetch application APK

To get the list of your installed applications:

loftwah

Methods of Signing with GPG

Last updated March 28, 2021

There are now two ways to approach this:

1. Using gpg and generating keys
2. Using Kryptonite by krypt.co

This Gist explains how to do this using gpg in a step-by-step fashion. Kryptonite is actually wickedly easy to use-but you will still need to follow the instructions