Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> writes:
> On 2/27/23 08:36, Tom Lane wrote:
>> If it was based on something like "du", perhaps the measurement
>> was fooled by the fact that most of the data files will be hard-linked
>> between the old and new clusters.
> Does that happen without the --link option?
No, but the OP didn't mention whether he used that, and even if he
didn't say it explicitly the pg_upgradecluster wrapper might've
supplied it.
regards, tom lane