[emmjay]

> A single EBS volume allows 10k IOPS max. To get the maximum performance out of an EBS volume, it has to be of a maximum size and attached to an EBS-optimized EC2 instance.

Out of date; EBS volumes can be up to 20k IOPS per volume and what is "maximum size"? To get the maximum performance out of a volume depends on workload, the instance size you've attached it to (rather than EBS Optimization) and the number of IOPS provisioned, and whether you've prewarmed it from a snapshot restore or not.

> A standard block size for an EBS volume is 16kb.

A block can be 1kb -> 256kb in size. It depends on the application.

> EBS volumes have a volume type indicating the physical storage type. The types called “standard” (st1 or sc1) are actually old spinning-platter disks, which deliver only hundreds of IOPS — not what you want unless you’re really trying to cut costs. Modern SSD-based gp2 or io1 are typically the options you want.

The ST1/SC1 wording is misleading. You only need '100s' of IOPS when dealing with big blocks for ST1, and SC1 isn't performance oriented at all.

[trowawee]

Might be more helpful to make a PR, rather than comment here. It'll take about the same amount of time.

[ranman]

Any IOP on EBS is measured in 16kb granularity. Not the same as block size but helpful to know because it lets you set your read ahead and other values to not lower than 16kb. At least this was the case for many years. Trying to find the official docs now.