This doesn’t seem to provide higher write availability, and if the read replicas are consistent with the write replica this design must surely degrade write availability as it improves read availability, since the write replica must update all the read replicas.
This also doesn’t appear to describe a higher durability design at all by normal definitions (in the context of databases at least) if it’s async…?
I think you may have misunderstood the GP and are perhaps misusing terminology. You cannot meaningfully scale vertically to improve write availability, and if you care about availability a single machine (and often a primary/secondary setup) is insufficient.
Even if you only care about scaling reads, eventually the 1:N write:read replica ratio will become too costly to maintain, and long before you reach that point you likely sacrifice real-time isolation guarantees to maintain your write availability and throughput.
No loss of committed transactions is acceptable to any serious business.
>I work at Neon
In my opinion, distributed DB solutions without synchronous write replication are DOA. Apparently a good number of people don't share this opinion because there's a whole cottage industry around such solutions, but I would never touch them with a 10 foot stick.