On Tue, 2021-11-23 at 13:51 -0600, Justin Pryzby wrote:
>
> I guess you're concerned for someone who wants to be able to run pg_upgrade and
> preserve the ability to start the old cluster in addition to the new.
Right. What I'm worried about is, if disk space or write performance on
the new cluster is a concern, then having a copy-mode upgrade silently
use copy-on-write could be a problem if the DBA needs copy mode to
actually copy.
--Jacob