> note that the local NVMe setup does have backups and WAL-archival to S3, which provides data-durability with RPO of 10s of seconds.
That's good, it provides a reasonable level of RPO, although I prefer just 0. But with this the RTO (or, equivalently, the downtime) is potentially quite large.
> Even with HA setup I expect performance difference to be similar across systems (may be slightly lesser)
I have done some benchmarks and I have observed a 24-27% performance penalty for semi-sync replication on instances using local NVMe. That's why I say this is non zero.
> In regards to default configs, that was intentional as default tuning is a differentiation across services and that needs to be measured. However we plan to add more configurability on postgres tuning in the future.
That's good, it provides a reasonable level of RPO, although I prefer just 0. But with this the RTO (or, equivalently, the downtime) is potentially quite large.
> Even with HA setup I expect performance difference to be similar across systems (may be slightly lesser)
I have done some benchmarks and I have observed a 24-27% performance penalty for semi-sync replication on instances using local NVMe. That's why I say this is non zero.
> In regards to default configs, that was intentional as default tuning is a differentiation across services and that needs to be measured. However we plan to add more configurability on postgres tuning in the future.
That'd be great.