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Comment by mattlord | Hacker News Reader

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mattlord·

It's open source. If you want to understand exactly how, you certainly can! :-)

https://github.com/vitessio/vitess

https://vitess.io/docs/reference/vreplication/

https://vitess.io/docs/reference/features/vtgate-buffering/

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He can't. It's not a reference, just a bunch of CLI examples. Please learn what is the reference. Even docs is a BS, wonderful product. Overall this article is a typical advertising and clickbait..

The code is open source though, you can read it. The cli examples point you towards the relevant bits of the actual database code to read.

For my own sake, I'm not sure what is so surprising here. "Turn up a hot second replica and fail over to it intentionally behind a global load balancer." Is pretty well trodden ground.

> The code is open source though, you can read it

Thank you! :D

> Is pretty well trodden ground.

YES!! But the article point us to it's a 400TB+ w/o downtime migration. This is impossible. That why is looks like clickbait and advertising of a product.

I will simply point out that I'm aware of larger zero down-time migrations, like this one: https://www.youtube.com/watch?v=ih97gwNmkRA

Thank you for the link but it's not the same case ;) Google used storage switching which has migration in mixed mode, i.e. migration on demand when data migrated due user access to. API had compatibility layer to read/write from/to both storage systems (i built kind of this migration mechanism about decade ago). And google spend about 8 years for the migration which ok. And the article about Database migration which can be periodical process (critical scheme changes for example) and they describe it to us. Take snapshot and racing with snapshot overhead changes and etc. I think we can let's over here. It's not a zero downtime solution cuz it's not exists.

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