Unrecoverable data corruption w/ ZFS, how do I fix?

If I run into a situation where ZFS has checksum errors on the data-drive when resilvering, how do I address it?

Theoretical Situation: 2-drive mirrors. One drive goes bad, hot-spare hops in and starts resilvering.

  1. If it notices checksum errors on the one drive, then what?
  2. That data is corrupt right?
  3. How will I know?
  4. Is it logged anywhere?
  5. How do I go about fixing it with backup data?
  6. It’s a “block” that’s bad, so how can I replace a block?
  7. Is there a way to know which files were associated with that bad block?

I wanna know what I should do when disaster strikes because if it’s too much trouble, I might go with 3-drive mirrors instead.