> You’re also missing an important factor: Many drives now reserve some space that cannot be used by the consumer so they have extra space to work with. This is called factory overprovisioning.

This has always been the case, thus why even a decade ago the “pro” drives were odd sizes like 120g vs 128g.

Products like that still exist today and the problem tends to show up as drives age and that pool shrinks.

DWPD and TB written like modern consumer drives use are just different ways of communicating that contract.

FWIW I’d you do a drive wide discard and then only partition 90% of the drive you can dramatically improve the garbage collection slowdown on consumer drives.

In the world of ML and containers you can hit that if you say have fstrim scheduled once a week to avoid the cost of online discards.

I would rather have visibility into the size of the reserve space through smart, but I doubt that will happen.