Strangely enough SHA-512 is actually (50%) faster than -256:
> ZFS actually uses a special version of SHA512 called SHA512t256, it uses a different initial value, and truncates the results to 256 bits (that is all the room there is in the block pointer). The advantage is only that it is faster on 64 bit CPUs.
Re:How does rsync work?
by slavik81 on Saturday July 02, 2022 @04:02PM
(#31961862)
It seems that SHA512t256 is another name for SHA-512/256. It's a shame that the initialization is different from SHA-512, as it would have been very useful to be able to convert a SHA-512 hash into a SHA-512/256 hash.
* https://openzfs.github.io/openzfs-docs/Basic%20Concepts/Chec...
* https://people.freebsd.org/~asomers/fletcher.pdf
* https://en.wikipedia.org/wiki/Fletcher%27s_checksum
Strangely enough SHA-512 is actually (50%) faster than -256:
> ZFS actually uses a special version of SHA512 called SHA512t256, it uses a different initial value, and truncates the results to 256 bits (that is all the room there is in the block pointer). The advantage is only that it is faster on 64 bit CPUs.
* https://twitter.com/klarainc/status/1367199461546614788