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Controlling and monitoring I/O performance to SVMs by using Storage QoS

You can control the input/output (I/O) performance to Storage Virtual Machines (SVMs) with FlexVol volumes by assigning these SVMs to Storage QoS policy groups. For example, you may want to control I/O performance to ensure that workloads achieve specific performance objectives or you may want to control I/O performance so that you can throttle a workload that negatively impacts other workloads. Storage QoS is supported on clusters that have up to eight nodes.

About this task

Policy groups enforce maximum throughput limits (for example, 100 MB/s). However, you can create a policy group without specifying a maximum throughput, so that you can monitor performance before you control the workload.

You can also assign FlexVol volumes, LUNs, and files to policy groups.

Following are requirements for assigning an SVM to a policy group:
  • The SVM that you assign must be the same SVM to which the policy group belongs.

    You specify this SVM when you create the policy group.

  • If you assign an SVM to a policy group, then you cannot also assign the storage objects contained by that SVM to a policy group.

Steps

  1. Use the qos policy-group create command to create a policy group.
    Example
    The following command creates policy group pg-vs1 with a maximum throughput of 5,000 IOPS.
    cluster1::> qos policy-group create pg-vs1 -vserver vs1 -max-throughput 5000iops
  2. Use the vserver modify command with the -qos-policy-group parameter to assign an SVM to a policy group.
    Example
    The following command assigns the SVM vs1 to policy group pg-vs1.
    cluster1::> vserver modify -vserver vs1 -qos-policy-group pg-vs1
  3. Use the qos statistics commands to view performance data.
    Example
    The following command shows the performance of policy groups.
    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
    pg_vs1                   5008       19.56MB/s     2.45ms
    _System-Best-Effort        62       13.36KB/s     4.13ms
    _System-Background         30           0KB/s        0ms
  4. If necessary, use the qos policy-group modify command to adjust the policy group's maximum throughput limit.
    Example
    The following command modifies the maximum throughput for policy group pg-vs1 to 4,500 IOPS.
    cluster1::> qos policy-group modify pg-vs1 -max-throughput 4500iops