PowerScale OneFS 9.2.1.0 CloudPools Administration Guide

CloudPools and SmartQuotas

With SmartQuotas, an administrator can enforce storage limits for users. Recalling data from the cloud could cause users to exceed assigned storage limits.

When CloudPools archives files to cloud storage, it creates SmartLink files on local storage in place of the archived files. SmartLink files typically take up considerably less storage space than the archived files they replace. When users recall archived files from the cloud, the full files replace the SmartLink files in local storage. Depending on the type of quota that was configured in SmartQuotas, a recall could cause a user to exceed their quota.

There are several types of quota thresholds that can apply to the quota accounting metric.

Physical quotas

A physical quota is implemented by configuring SmartQuota with the --thresholds-on physicalsize option.

With physical quotas, when cloud data is recalled, the recalled file's physical size is used in the quota accounting metric. When users are close to their assigned quotas, a recall can exceed the quota.

For example, suppose a user's quota is 500 MB, and files older than six months are archived to the cloud. This saves the user 250 MB of space, as the SmartLink files take up relatively little local storage space. In the meantime, the user has added more files and now has 400 MB of data in local storage. If the user recalls files from the cloud that would take up more than 100 MB of storage, the user would exceed the quota.

Logical quotas

A logical quota is implemented by configuring SmartQuota with the --thresholds-on fslogicalsize option.

With logical quotas, when cloud data is recalled, the SmartLink file's logical size is used in the quota accounting metric rather than the recalled physical size. Using the logical size effectively mitigates the risk of exceeding quotas that exists with physical quotas.

As a storage administrator, you might want to use logical quotas where CloudPools is in effect. Otherwise, if physical quotas are used, ensure that your users are aware of the possibility of exceeding the quota and how best to mitigate the issue.