Controlling the performance impact of RAID-level scrubbing

When Data ONTAP performs a RAID-level scrub, it checks the disk blocks of all disks on the storage system for media errors and parity consistency.

Considerations

When RAID-level scrubbing and mirror verification 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 by both operations has a medium impact.

Note: If there are times during the day where the load on your storage system is decreased, you can also limit the performance impact of the automatic RAID-level scrub by changing the start time or duration of the automatic scrub.

Step

Enter the following command:options raid.scrub.perf_impact impact
impact can be high, medium, or low.
high means that the storage system uses most of the system resources—CPU time, disks, and disk-to-controller bandwidth—available for scrubbing; this setting can heavily affect storage system performance, but the scrub will complete in less time.

low means that the storage system uses very little of the system resources; this setting lightly affects storage system performance, and the scrub will take longer to complete.

The default value for impact is low.

Parent topic: Controlling the impact of RAID operations on system performance

Related concepts

How you schedule automatic RAID-level scrubs

How Data ONTAP uses RAID to protect your data and data availability

Controlling the performance impact of plex resynchronization

Controlling the performance impact of mirror verification