We debated having a copy pool when doing our DD setup. We finally decided

that using a daily DD snapshot was an acceptable solution. We take a

Rick

The problem with that is that you'd just be replicating a logical
corruption. So unless you noticed it before your last snapshot expired, you
be stuck.
Obvoliusly a simple solution would be to have a copy stpool on exactly the
same DD - inefficient copying wize, but it would dedupe down to nothing.