Anyway, it is an annoyance but once you put any kind of "real" workload on the system it will go away. The opportunistic nature of the scrub just takes over the aggregate from 0030-0530hrs for no apparent reason when the system is otherwise idle. Put real user workloads on there and the scrub drops back down to background noise. We actually "reintroduced" this behavior on another system that was in service for 3 years and we decommissioned all the workloads on it. Sure enough, OCPM started alerting us that the aggregate was over-utilized every evening (and even longer on Sundays).