"So what does your evil RAM need to do in order to actually overwrite your good data with corrupt data during a scrub? Well, first it needs to flip some bits du

"So what does your evil RAM need to do in order to actually overwrite your good data with corrupt data during a scrub? Well, first it needs to flip some bits during the initial read of every block that it wants to corrupt. Then, on the second read of a copy of the block from parity or redundancy, it needs to not only flip bits, it needs to flip them in such a way that you get a hash collision. " This is not true. If the 2nd read is good, the hash matches, and then the RAM flips bits before or during the write, it will corrupt data. The potentially good news is that this bad write could get caught on a subsequent scrub. The bottom line is, without ECC RAM, I/O is not particularly trustworthy with any filesystem, including ZFS.