Plex resynchronization ensures that both plexes of a mirrored aggregate are identical. You can control the performance impact of plex resynchronization by using the raid.resync.perf_impact option.
When plex resynchronization and RAID data reconstruction are running at the same time, Data ONTAP limits the combined resource utilization to the greatest impact set by either operation. For example, if raid.resync.perf_impact is set to medium and raid.reconstruct.perf_impact is set to low, the resource utilization by both operations has a medium impact.
You should set this option to the same value for both nodes in an HA configuration.
impact can be high, medium, or low.
high means that the storage system uses most of the system resources available for plex resynchronization; this setting can heavily affect storage system performance, but the resynchronization finishes sooner.
low means that the storage system uses very little of the system resources; this setting lightly affects storage system performance, but the resynchronization takes longer to complete.
The default impact is medium.