UFS vs ZFS non-ECC/Amount of RAM

[therunningotaku]

Just wondering - if I ran FreeNAS with UFS, would I still be able to create mirror volumes and would having non-ECC memory mean that my data is secure if I had a fault in the RAM?
For non-ECC ram, if there aren't any new faults in the data, will the data be safe? From what I read, errors are consistent (the same DIMM will always cause an error in the same bit of memory on it), so if you run mentest a couple times, and no new errors pop up, would there be a problem?
Also, why does having less than 8GB of RAM cause a ZFS volume to become dangerous/unstable? I've looked around, and everyone seems to reccomend it, but other than from a performance perspective I can't see why it would case me to lose my data.
Sorry for all the questions, I'm new to FreeNAS.

 

[Ericloewe]

Not having ECC is always dangerous if you value your data. ZFS just makes the problem a bit worse because it'll quickly propagate. Your data is most certainly not safe without ECC RAM just because you're using UFS.
Additionally, there's no guarantee that problems won't develop after the server is tested, that they'll be anywhere close to predictable or that Memtest will find the error.

As for the minimum requirement, 8GB is the smallest amount that has been empirically enough not to cause problems. Nobody knows for sure what's wrong, exactly, but fixing that is a low priority, considering the performance would be unacceptable for most people anyway.