AFAIK zfs doesn't use erasure coding. It has a checksum for each block. Together with redundant storage of blocks, this allows it to determine which block is corrupt when two copies of the same block have different contents.

Redundant storage of the meta data - not the actual blocks. But at least you know they're corrupted if the become corrupted ;)

Nope, all blocks, unless wikipedia is wrong or I am completely misunderstanding the following:

"When a block is accessed, regardless of whether it is data or meta-data, its checksum is calculated and compared with the stored checksum value of what it "should" be. If the checksums match, the data are passed up the programming stack to the process that asked for it; if the values do not match, then ZFS can heal the data if the storage pool provides data redundancy (such as with internal mirroring), assuming that the copy of data is undamaged and with matching checksums."

https://en.wikipedia.org/wiki/ZFS

"ZFS can heal the data IF the storage pool provides data redundancy"

You can configure ZFS either with or without redundancy.

Yes, which is why I said "Together with redundant storage of blocks" in my original comment.