[Snelius]

> 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.

[joshuamorton]

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

[Snelius]

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.