Right, but I think you're kinda missing a lot of the tangible benefits here. This IMO is just reinforcing the idea of "unlimited" IOPS. You can't physically use the totality of IOPS available on the drives.
Even if you can't saturate them, even with low CPU cores, latency is drastically better which is highly important for database performance.
Having low latency is tangibly more important than throughput or number of IOPS once your dataset is larger than RAM no matter how many CPU cores you have.
Chasing down p95s and above really shine with NVMes purely from having whatever order of magnitude less latency.
Less latency also equates to less iowait time. All of this just leads to better CPU time utilization on your database.
Not all AWS instance types support NVMe drives. It's not the same as normal attached storage.
I'm not really sure your arguments are in good faith here tho.
This is just not a configuration you can trivially do while maintaining durability and HA.
There's a lot of hype going the exact opposite direction and more separation of storage and compute. This is our counter to that. We think even EBS is bad.
This isn't a setup that is naturally just going to beat a "real server" that also has local NVMes or whatever you'd do yourself. This is just not what things like RDS or Aurora do, etc. Most things rely on EBS which is significantly worse than local storages. We aren't really claiming we've invented something new here. It's just unique in the managed database space.
It's more than just shutting down. You'd have to have an actual failure. Data isn't lost on a simple restart. It'd require 3 nodes to die in 3 different AZs.
While that's not impossible, the reality is that's very low.
So simply restarting nodes wouldn't trigger restoring from backup, but yes, in our case, replacing nodes entirely does require that node to restore from a backup/WALs and catch back up in replication.
EBS doesn't entirely just solve this, you still have failures and still need/want to restore from backups. This is built into our product as a fundamental feature. It's transparent to users, but the upside is that restoring from backups and creating backups is tested every day multiple times per day for a database. We aren't afraid of restoring from backups and replacing nodes by choice or by failure. It's the same to us.
We do all of the same operations already on EBS. This magic is what enables us to be able to use NVMe's since we treat EBS as ephemeral already.
Unlimited in this context just means you're going to be CPU limited before you hit limits on IOPS. It'd be technically not possible to be bottlenecked on IOPS.
That might not be 100% true, but I've never seen a RDBMS be able to saturate IOPS on a local NVMe. It's some quite specialized software to leverage every ounce of IOPS without being CPU bottlenecked first. Postgres and MySQL are not it.
Even if you can't saturate them, even with low CPU cores, latency is drastically better which is highly important for database performance.
Having low latency is tangibly more important than throughput or number of IOPS once your dataset is larger than RAM no matter how many CPU cores you have.
Chasing down p95s and above really shine with NVMes purely from having whatever order of magnitude less latency.
Less latency also equates to less iowait time. All of this just leads to better CPU time utilization on your database.