Without error coding only a perfect channel can give lossless performance. But with error coding even a fairly lossy channel can give performance that is arbit

Without error coding only a perfect channel can give lossless performance. But with error coding even a fairly lossy channel can give performance that is arbitrarily close to lossless, depending only on how much capacity you're willing to waste. As the number of blocks on our storage devices grows their the probability that there is at least one with an error goes up. Even with raid5 the probability that there are two errors in one stripe unit at the same time can become non-negligible. Worse, for raid5/6 normally the system is defendant on the device detecting corruption. When it doesn't, the raid will not only not fix but potentially propagate the corruption to other data. (I understand that ZFS at least can use its internal checksums to handle this case).