[logsr]

Amazing presentation. It really helps to understand the concepts.

The only add is that it understates the impact of SSD parallelism. 8 Channel controllers are typical for high end devices and 4K random IOPS continue to scale with queue depth, but for an introduction the example is probably complex enough.

It is great to see PlanetScale moving in this direction and sharing the knowledge.

[bddicken]

Thank you for the info! Do you have any good references on this for those who want to learn more?

[logsr]

Just going off specs sheets from manufacturers and reviews (mostly consumer products, so enterprise should be the same or better).

There are only a few major NAND manufacturers: Samsung, Micron, Kioxia / Western Digital, SK Hynix, and their branded products are usually the best.

There are also several 3rd party controller developers: Phison, Marvell, Silicon Motion, which I think are the largest, and then a bunch of others.

I hadn't looked at this in a couple years, so 16 channel controllers are more common now, but only on high end enterprise devices.

4KB random read/write specs are definitely not trustable without testing. They are usually at max queue depth and, at least for consumer devices, based on writing to a buffer in SLC mode, so they will be a lot lower once the buffer is exhausted. Enterprise specs might be more realistic but there isnt as much public testing data available.