You use mirror verification to ensure that the two plexes of a synchronous mirrored aggregate are identical. You can control the speed of mirror verification, and its effect on system resources, by using the raid.verify.perf_impact option.
When mirror verification and RAID-level scrubbing 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.verify.perf_impact is set to medium and raid.scrub.perf_impact is set to low, the resource utilization of both operations has a medium impact.
For more information about synchronous mirroring, see the Data ONTAP Data Protection Tape Backup and Recovery Guide for 7-Mode.
impact can be high, medium, or low.
high means that the storage system uses most of the system resources available for mirror verification; this setting can heavily affect storage system performance, but the mirror verification finishes sooner.
low means that the storage system uses very little of the system resources; this setting lightly affects storage system performance, but the mirror verification takes longer to complete.
The default impact is low.