You can use the min-throughput field for a policy group to define a throughput floor for storage object workloads (QoS Min). You can apply the policy group when you create or modify the storage object. Starting with ONTAP 9.8, you can specify the throughput floor in IOPS or MBps, or IOPS and MBps.
About this task
Starting with ONTAP 9.5, you can use a non-shared QoS policy group to specify that the defined throughput floor be applied to each member workload individually. This is the only condition in which a policy group for a throughput floor can be applied to multiple workloads.
Set -is-shared=false for the qos policy-group create command to specify a non-shared policy group.
Throughput to a workload might fall below the specified floor if there is insufficient performance capacity (headroom) on the node or aggregate.
A storage object that is subject to a QoS limit must be contained by the SVM to which the policy group belongs. Multiple policy groups can belong to the same SVM.
It is a QoS best practice to apply a policy group to the same type of storage objects.
A policy group that defines a throughput floor cannot be applied to an SVM.
- Check for adequate performance capacity on the node or aggregate, as described in Identifying remaining performance capacity.
- Create a policy group: qos policy-group create -policy group policy_group -vserver SVM -min-throughput qos_target -is-shared true|false
For complete command syntax, see the man page for your ONTAP release. You can use the qos policy-group modify command to adjust throughput floors.
Example
The following command creates the shared policy group pg-vs2 with a minimum throughput of 1,000 IOPS:
cluster1::> qos policy-group create -policy group pg-vs2 -vserver vs2 -min-throughput 1000iops -is-shared true
Example
The following command creates the non-shared policy group pg-vs4 without a throughput limit:
cluster1::> qos policy-group create -policy group pg-vs4 -vserver vs4 -is-shared false
- Apply a policy group to a volume or LUN: storage_object create -vserver SVM -qos-policy-group policy_group
For complete command syntax, see the man pages. You can use the storage_object modify command to apply a different policy group to the storage object.
Example
The following command applies policy group pg-app2 to the volume app2 :
cluster1::> volume create -vserver vs2 -volume app2 -aggregate aggr1 -qos-policy-group pg-app2
- Monitor policy group performance:qos statistics performance show
For complete command syntax, see the man page.
Monitor performance from the cluster. Do not use a tool on the host to monitor performance.
Example
The following command shows policy group performance:
cluster1::> qos statistics performance show
Policy Group IOPS Throughput Latency
-------------------- -------- --------------- ----------
-total- 12316 47.76MB/s 1264.00us
pg_app2 7216 28.19MB/s 420.00us
_System-Best-Effort 62 13.36KB/s 4.13ms
_System-Background 30 0KB/s 0ms
- Monitor workload performance:qos statistics workload performance show
For complete command syntax, see the man page.
Monitor performance from the cluster. Do not use a tool on the host to monitor performance.
Example
The following command shows workload performance:
cluster1::> qos statistics workload performance show
Workload ID IOPS Throughput Latency
--------------- ------ -------- ---------------- ----------
-total- - 12320 47.84MB/s 1215.00us
app2-wid7967 7967 7219 28.20MB/s 319.00us
vs1-wid12279 12279 5026 19.63MB/s 2.52ms
_USERSPACE_APPS 14 55 10.92KB/s 236.00us
_Scan_Backgro.. 5688 20 0KB/s 0ms
You can use the qos statistics workload latency show command to view detailed latency statistics for QoS workloads.