How to reduce workload driven disk utilization in ONTAP 9
Applies to
ONTAP 9
Issue
- Disk IO latency is appearing due to too many operations at the same time due to user workload.
- Multiple volumes from a particular SVM/aggregate report high latency.

- Using Active IQ Unified Manager or
qos statistics volume latency show, latency is shown to be in the Disk or Aggregate Processing (Active IQ Unified Manager), and latency is actively impacted on the target volume.
Example:
cluster1::> qos statistics volume latency show -vserver svm1 -volume vol1 Workload ID Latency Network Cluster Data Disk QoS Max QoS Min NVRAM --------------- ------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ---------- -total- - 4.71ms 185.00us 7.00us 468.00us 4.04ms 0ms 0ms 11.00us vol1 32140 22.22ms 86.00us 125.00us 904.00us 21.11ms 0ms 0ms 1.00us -total- - 4.58ms 253.00us 7.00us 991.00us 3.32ms 0ms 0ms 11.00us vol1 32140 29.69ms 90.00us 162.00us 2.61ms 26.82ms 0ms 0ms 1.00us -total- - 2.55ms 229.00us 8.00us 589.00us 1.71ms 0ms 0ms 13.00us vol1 32140 18.84ms 61.00us 314.00us 136.00us 18.32ms 0ms 0ms 1.00us -total- - 4.33ms 198.00us 9.00us 1221.00us 2.88ms 0ms 0ms 13.00us vol1 32140 177.16ms 113.00us 226.00us 108.03ms 68.79ms 0ms 0ms 2.00us
- The qos command
qos statistics workload resource diskshow listUser-Defaultas the top DISK workload.
Example:
cluster1::> qos statistics workload resource disk show -node nodeB Workload ID Disk Number of HDD Disks --------------- ------ ----- ------------------- -total- - 98% 44 User-Default - 83% 44 _Efficiency_... - 10% 44 _WAFL - 3% 44 _RAID - 2% 44
