Let's say you have 6 drives in raidz2. If you have a 1% silent failure chance per block, then writing a set of 6 blocks has a 0.002% silent failure rate. And ZFS doesn't immediately verify writes, so it won't try again.
If that's applied to 4KB blocks, then we have a 0.002% failure rate per 16KB of data. It will take about 36 thousand sets of blocks to reach 50% odds of losing data, which is only half a gigabyte. If we look at the larger block ZFS uses internally then it's a handful of gigabytes.
And that's without even adding the feature where writing one block will corrupt other blocks.
Let's say you have 6 drives in raidz2. If you have a 1% silent failure chance per block, then writing a set of 6 blocks has a 0.002% silent failure rate. And ZFS doesn't immediately verify writes, so it won't try again.
If that's applied to 4KB blocks, then we have a 0.002% failure rate per 16KB of data. It will take about 36 thousand sets of blocks to reach 50% odds of losing data, which is only half a gigabyte. If we look at the larger block ZFS uses internally then it's a handful of gigabytes.
And that's without even adding the feature where writing one block will corrupt other blocks.