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0 pointsjansommer4mo ago0 comments

This is super confusing. Check out the RDS Postgres calculator with gp3:

> General Purpose SSD (gp3) - Throughput > gp3 supports a max of 4000 MiBps per volume

But the docs say 2000. Then there's IOPS... The calculator allows up to 64.000 but on [0], if you expand "Higher performance and throughout" it says

> Customers looking for higher performance can scale up to 80,000 IOPS and 2,000 MiBps for an additional fee.

[0] https://aws.amazon.com/ebs/general-purpose/

0 comments

nijave4mo ago

RDS PG stripes multiple gp3 volumes so that's why RDS throughput is higher than gp3

I think 80k IOPs on gp3 is a newer release so presumably AWS hasn't updated RDS from the old max of 64k. iirc it took a while before gp3 and io2 were even available for RDS after they were released as EBS options

Edit: Presumably it takes some time to do testing/optimizations to make sure their RDS config can achieve the same performance as EBS. Sometimes there are limitations with instance generations/types that also impact whether you can hit maximum advertised throughput

mkesper4mo ago

Only if you allocate (and pay for) more than 400GB. And if you have high traffic 24/7 beware of "EBS optimized" instances which will fall down to baseline rates after a certain time. I use vantage.sh/rds (not affiliated) to get an overview of the tons of instance details stretched out over several tables in AWS docs.

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