How to ace coding interviews; and scaling tips from Netflix & Shopify

My TL;DR style notes from articles I read today.

How to ace the coding interview, by an ex-Facebook interviewer

• Don’t rush to write code. Think about the problem first and think out loud.
• Ask as many questions as you have about the problem before starting to solve it.
• Don’t strive to impress with the right answer, talk about all approaches you can take and talk about the tradeoffs with each.
• Plan your solution with a pseudocode.
• Talk out loud about what you are doing while implementing the solution.
• Write comprehensive test cases.

Pro-tip by the author in case you are stuck: Some of the best problem solving happens when you can align the strength of a specific data structure to a problem’s bottleneck.

Full post here, 8 mins read

Tips for high availability

• Go for regional deployment, validate the change and then go for global deployment.
• Choose deployment windows during off-peak times for each geographical location.
• Any deploys triggered automatically should not be executed during off-work hours or weekends.
• Use testing & canary analysis to validate code before it is pushed to production.
• Deploy to production exactly what you tested.
• Know how to roll back any deploys quickly.
• Use preconditions to verify the expected state.

Full post here, 9 mins read

How Shopify manages petabyte-scale MySQL backup and restore

A few learnings from the post:

• Use incremental snapshots of data for backup after one initial full snapshot to reduce both storage and recovery times.
• Save on storage costs by deleting all but the last two copies for recovery purposes.
• To ensure data integrity, verify these last two backup iterations daily.
• Compress, encrypt and transfer the backup to offsite storage to build further security.
• Using snapshots this way is a more expensive process than more traditional backup technologies. But it reduces time and processing power for both the user and the service.

Full post here, 6 mins read

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