Modifying aggregate capacity thresholds

Several thresholds determine how much free space is required in an aggregate. In most cases, you should keep the default values, but you can modify them if they do not meet your needs.

About this task

You can define capacity thresholds for the following:

Aggregate free space ratio
The percentage of free space available in the aggregate. The threshold is 10 percent by default. The calculation for the ratio is: the aggregate's capacity minus the aggregate's used capacity divided by the aggregate's capacity.
Aggregate overcommitment ratio
The ratio between the amount of storage over provisioned in the aggregate and the free space available in the aggregate. The threshold is 500 percent by default. The calculation for the ratio is: the total allocated capacity on the aggregate minus the aggregate's used capacity divided by the aggregate's free capacity. The total allocated capacity on the aggregate is derived from all volumes, whether they are thick or thin provisioned.

For example, suppose a 1,000 GB aggregate has 100 GB of free space and contains two volumes:

  • A 1,000-GB thin-provisioned volume with 600 GB used size
  • A 300-GB thick-provisioned volume

The overcommitment ratio for this aggregate is: 1,300 minus 900 divided by 100 which translates to 400 percent. If you wanted to provision a 200-GB thin-provisioned volume on this aggregate, the overcommitment would increase: 1,500 minus 900 divided by 100 which translates to 600 percent. Provisioning this volume would cross the threshold.

Ratio of EBS free capacity to S3 used data capacity, per aggregate
This ratio defines how much free space is required on EBS storage when tiering data to Amazon S3. The ratio is important for disaster recovery scenarios because as data is read from S3, ONTAP Cloud moves the data to EBS storage to provide better performance. If there is not sufficient space, then ONTAP Cloud cannot move the data.

If an aggregate crosses either of these thresholds, Cloud Manager displays a notification in the working environment page, notifying you that additional disks are needed.

Steps

  1. In the upper-right hand corner of the Cloud Manager console, click the task-drop down list, and then select Settings.
  2. Under Aggregate Capacity Thresholds, change the percentages and click Save.

Result

Cloud Manager updates the threshold percentages and notifies users when they are reached.