 While ECC is nice to have, it is not a necessity to maintain the integrity of your CFS pool. There are a series of redundancies and checks that go into every single write operation on ZFS. So if a bit were flipped in memory, the integrity would fail on that write and it would fail to write that data. Now the advantage of ECC is potentially it could catch that bit flip and then that data would actually get written because it would then pass all the integrity tests, but it won't write data that's bad to the ZFS pool. So it's nice to have ECC, but as I said, not necessary, I have a video where I dive deeper into how ZFS writes work. It's linked in the description below.