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Learn how to design large-scale systems

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Re: Learn how to design large-scale systems

#21

Post by 0xbadcafebee »

tryonqc wrote: post #6
nwsm wrote: post #2

This is a nice followup to the web architecture post yesterday

He/she means this one: https://news.ycombinator.com/item?id=17517155 Today's post is way more in-depth. Good follow-up indeed.

Obligatory pedantic HN grammar comment: on the outside chance that the gp's gender is not binary, the word 'they' is a good stand-in gender neutral pronoun to 'he/she'. You also have at least 14 alternatives to choose from (https://en.wikipedia.org/wiki/Third-person_pronoun#Summary) and two more if you're at a Renaissance faire (https://en.wikipedia.org/wiki/Third-person_pronoun#Historica...). For the grammar snobs, this convention has existed since the 16th century.

Re: Learn how to design large-scale systems

#22

Post by tw1010 »

sillysaurus3 wrote: post #9

Note that HN, a top-1000 site in the US, runs on a single box via a single racket process. "The key to performance is elegance, not battalions of special cases."

While I agree with you, a lack of knowledge about this stuff will unfortunately not help you pass any interviews.

Re: Learn how to design large-scale systems

#23

Post by d-- »

I'm teaching an intro distributed systems class and would like to share this with my students. I was wondering about how general the linked interview prepwork is. Are the Anki cards and sample interview questions mostly from large companies (FB, Google, MS) or also applicable to interviewing at smaller places?

At first look, seems like these are fairly general questions, which is great.

Re: Learn how to design large-scale systems

#24

Post by twistedpair »

pc86 wrote: post #11
gnahckire wrote: post #8

Earlier quoted context omitted.

It also makes changing your DB a lot easier since APIs using the DAL don't need to be updated since they're DB agnostic -- you "only" need to update the DAL API.

How often does one change the DB backing a live production application?

I've done it twice. If you're experiencing significant growth or change in access patterns, you may for example go from Postgres to a KV store.

In one of the cases where I had to switch, we swapped from Cassandra to S3 for 100x OpEx savings since C* couldn't scale cost effectively to our needs, so we rolled a database on top of S3 instead that well out performed C* for our use case (e.g. need to export a 3B row CSV in a minute?).

Re: Learn how to design large-scale systems

#25

Post by blattimwind »

Lunatic666 wrote: post #19
pc86 wrote: post #11

Earlier quoted context omitted.

How often does one change the DB backing a live production application?

I also don't think it's a good idea. If you don't use the database specific functions out of fear you aren't able to switch anymore, you are probably wasting a lot of potential performance.

I think "changing the DB" likely referred to schema changes, not swapping out the DBMS.

Re: Learn how to design large-scale systems

#26

Post by byebyetech »

madethemcry wrote: post #13

Oh interesting, I have never seen Anki ( https://apps.ankiweb.net/ ) being used for large blocks of source code. Anki is an open source application (desktop + mobile) for spaced repetition learning (aka flashcards). It's a very popular tool among people who want to learn languages (and basically anything else you want to remember). There are many shared decks ( https://ankiweb.net/shared/decks/ ). Creating and format…

I don't think Anki supposed to be used that way. Each card should be recallable under 10 seconds. So it should be only few lines of content. More content you put in one Anki card, it will take you more time and eventually you will stop looking at the card. A failure scenario.

Re: Learn how to design large-scale systems

#27

Post by GordonS »

pc86 wrote: post #11
gnahckire wrote: post #8

Earlier quoted context omitted.

It also makes changing your DB a lot easier since APIs using the DAL don't need to be updated since they're DB agnostic -- you "only" need to update the DAL API.

How often does one change the DB backing a live production application?

I've never done it in my 16+ year working life.

I used to design systems so this was possible, but eventually realised it just wasn't needed - I was adding more abstraction and complexity for no reason.

Re: Learn how to design large-scale systems

#28

Post by moduspol »

sillysaurus3 wrote: post #9

Note that HN, a top-1000 site in the US, runs on a single box via a single racket process. "The key to performance is elegance, not battalions of special cases."

HN has the luxury of being able to make few high level changes over years, though. It might be tougher to maintain that single box elegance and performance if they were adding new features every month or two (which is much more applicable to the rest of us).

Re: Learn how to design large-scale systems

#29

Post by bandwitch »

agentultra wrote: post #7

I'd add a section on using TLA+ as a design tool. Diagrams and rules of thumb are useful but they don't catch errors or help you discover the correct architecture. See the Amazon paper [0] on their use of TLA+ in designing (and trouble-shooting) services. [0] https://lamport.azurewebsites.net/tla/formal-methods-amazon....

I feel TLA+ would be too much to ask in a system interview which is what this site is about.

In case anybody is interested, there is a nice talk by Hillel Wayne on youtube (https://www.youtube.com/watch?v=_9B__0S21y8) that provides a high-level overview on what TLA+ is about.

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