IOPS and MiB/s Limits on Volumes and Folders

You can set both IOPS (input/output requests per second) and MiB/s (mebibytes per second) limits when you set up a Quality of Service policy for a volume or Storage Policy-Based Management (SPBM) for Virtual Volumes.

You specify the IOPS and MBps limits separately. The input/output requests are throttled when either the IOPS limit or the MBps limit is met.

The default upper bound value for both the IOPS and the MiB/s is unlimited. The lower bound for IOPS is 256 requests. The lower bound for the MiB/s value is calculated as greater than or equal to the IOPS limit multiplied by the volume block size. This way the MiB/s value does not throttle the IOPS for the volume.

If the volume contains folders, then the IOPS and MiB/s limits work as an aggregate. The input/output requests to the volumes under the folder are throttled when the cumulative IOPS of all the volumes under that folder exceeds the folder IOPS limit or when the cumulative throughput of all the volumes under that folder exceeds the folder MiB/s limit. When this happens, all the volumes are throttled equally.

You can set these limits when you create or edit either a volume or a folder. You can set separate limits for both volumes and folders. You can view the limits for volumes and folders on the Performance tab at:

Manage → Data Storage → Performance

If you are creating or editing a folder, you can set the limits at the folder level that are in addition to the volume-level limits. The default limits are at the volume level. You can view the limits on the Folder tab at:

Manage → Data Storage → Folder

You can monitor the throughput and bandwidth for the array, the volumes, and the folders by selecting:

Monitor → Performance