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Comment by Sweepi | Hacker News Reader

... and it was a disappointment. Apple had the one-in-30-years opportunity to ship a state of the art file system, and they choose to not have protection against user data bit rot (against meta data rot they choose yes, which is nice), which ZFS and others had for .. idk, a decade at this point?

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Why would this be needed, if every single Apple device uses flash memory which provides its own guarantees against bitrot?

Because those guarantees aren't guarantees, more like partial mitigation.

modern flash ECC may not always be able to correct but it is able to DETECT almost any number of bits wrong, so that is just as good as ZFS - if the data is banged - you'll know.

Is that a distinction between modern SSD drives and the small spinning drives? The ECC? Is a modern SSD more resistant to corruption than a modern spinning drive?

And the drives I’m talking about the external usb drives everyone (me) have dangling off their machines (notably things like Time Machine and such).

and Apple doesn’t care about people connecting 3rd party hardware to Macs

How feasible is it to add those kinds of features? Or would that have to be baked-in from the start?

I wrote a small utility to find and dedup[0] using APFS features and had to poke around the user exposed metadata quite a bit. The short answer is probably. Metadata is extendable and there are things that work similarly already (encryption, and clone ids, for example).

0 - https://github.com/ttkb-oss/dedup

No data checksumming is one of the main reasons not to trust APFS for valuable data. Maybe it is fine on Apple SSDs, but what about terabytes of data on external disks?

Why checksum metadata if the SSD is so safe?

...because their "disks" all have hardware ECC?

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