Note that those numbers are terrible vs. a physical disk, especially latency, which should be < 1ms read, << 1ms write.
(That assumes async replication of the write ahead log to a secondary. Otherwise, write latency should be ~ 1 rtt, which is still << 5ms.)
Stacking storage like this isn’t great, but PG wasn’t really designed for performance or HA. (I don’t have a better concrete solution for ansi SQL that works today.)
- EBS typically operates in the millisecond range. AWS' own documentation suggests "several milliseconds"; our own experience with EBS is 1-2 ms. Reads/writes to local disk alone are certainly faster, but it's more meaningful to compare this against other forms of network-attached storage.
- If durability matters, async replication isn't really the right baseline for local disk setups. Most production deployments of Postgres/databases rely on synchronous replication -- or "semi-sync," which still waits for at least one or a subset of acknowledgments before committing -- which in the cloud lands you in the single-digit millisecond range for writes again.
The raw numbers are one thing, but the overall performance of pg is another. If you check out https://planetscale.com/blog/benchmarking-postgres-17-vs-18 for example, in the average QPS chart, you can see that there isn't a very large difference in QPS between GP3 at 10k iops and NVMe at 300k iops.
So currently I wouldn't recommend this new storage for the highest end workloads, but it's also a beta project that's still got a lot of room for growth! I'm very enthusiastic about how far we can take this!