Skip to main content
NetApp Knowledge Base

What are IOPs?

Last Updated:

Applies to

All storage systems


What are the performance characteristics of different op sizes in ONTAP 9?
  • Random IOPs will take more CPU and may have higher latency than sequential
    • Random IOPs blocks are read not in any order off of disk, like block 3, 12, 66, 1, etc.
    • Sequential IOPs blocks are read in order off of disk, like block 1, 2, 3, 4, etc.
  • Smaller operation sizes generally require more computation
    • In the example above of a 1 MB file, ONTAP has to go to disk 256 times and process 256 operations at 4kB vs only 16 at 64kB
  • ONTAP will handle over 64kB fine, but due to the normalization of operation sizes, latency may appear slightly higher
    • This is better in newer versions of ONTAP 9 compared to Data ONTAP 8
    • A 1 MB read size will have 16 WAFL requests of 64kB each in parallel
Are disk IOPS measured the same as frontend IOPS?
What causes IOPS?
  • ONTAP does not track IOPS for internal processes but uses different methods of accounting them.
  • IOPS are generated from user requests for all served data protocols (CIFS/FCP/iSCSI/NFS/NVMe*/S3).
    • The only exception is if you use set advanced; statistics start -object volume -counter repl_*_ops which will show SnapMirror IOPS.
    • The commands for qos statistics and the workload objects for statistics, as well as other commands are all user IOPS.
  • If a workload burst happens, then it must be investigated from the client end.

Additional Information


NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS and the use of this information or the implementation of any recommendations or techniques herein is a customer's responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.