Storage QOS maximum throughput limits can be defined in terms of:

A.
IOPS only

B.
MB/s only

C.
IOPS or MB/s

D.
IOPS and MB/s

Explanation:
Storage QoS workload management (available in clustered Data ONTAP 8.2 and later)
allows you to define service levels by creating policies that control the resources that can
be consume by individual files, volumes or LUNS or entire SVMs to manage performance
capacity limits (defined in terms of a maximum value for IOPS or MB/sec) on a group of
files or volumes or LUNs within an SVM or on the entire SVM.
Link: http://www.netapp.com/us/system/pdf-reader.aspx?pdfuri=tcm:10-113725-
16&m=wp-7191.pdf