Creating a SmartQoS Policy

A QoS policy is a group of I/O performance targets. This section describes how to dynamically allocate storage resources to meet a specified performance objective of a certain application.

Precautions

The user host aggregates I/Os for specific service models. As a result, the IOPS of services received by the storage system is lower than that delivered by the host application. If the IOPS upper limit in a QoS policy is set based on the IOPS of services delivered by the host application, the QoS policy cannot limit the IOPS of services on the storage system effectively. In this case, you can lower the IOPS upper limit or configure a bandwidth upper limit in the QoS policy.

Context

Procedure

  1. Choose Resources > Tuning > SmartQoS.
  2. Click Create.

    The Create QoS Policy page is displayed.

  3. Set a QoS policy name.

    • The name must be unique.
    • The name can only contain digits, letters, underscores (_), and hyphens (-), and must start with a digit or letter.
    • The name contains 1 to 63 characters.

  4. Select a QoS policy type.

    • Exclusive: Limits the performance upper limit of a single object. To configure basic parameters of a QoS policy of the exclusive type, perform the operations in 5.
    • Shared: Limits the total performance upper limits of the storage pool. To configure basic parameters of a QoS policy of the shared type, perform the operations in 6.

  5. Set basic parameters of a QoS policy of the exclusive type in either of the following ways, including By total performance upper limits and By read and write upper limits.

    • By total performance upper limits

      Table 1 describes related parameters.

      Table 1 Parameters of a QoS policy of the exclusive type

      Parameter

      Description

      Max. IOPS/GB

      Maximum number of read/write operations that can be performed on an object per second per GB.

      Max. IOPS

      Maximum IOPS of a single object, that is, the maximum number of read/write operations that can be performed on an object per second.

      NOTE:
      • If the value of Max. IOPS/GB is greater than 0, calculate the effective maximum IOPS in the QoS policy as follows:
        1. Calculate (IOPS/GB x Object capacity) + 100.
        2. Compare the calculation result obtained in 1 with Max. IOPS. The smaller of the two values is the effective maximum IOPS.

        Suppose that Max. IOPS/GB is 2, object capacity is 100 GB, and Max. IOPS is 1000. The effective maximum IOPS in the QoS policy is 300 (that is, 2 x 100 + 100), because 300 is smaller than 1000.

      • If Max. IOPS/GB is set to 0, the effective maximum IOPS in the QoS policy is Max. IOPS.

      Burst IOPS/Duration

      Maximum number of read/write operations that can be performed on an object per second within a specified period when the burst function is enabled.

      • Burst IOPS: maximum number of read/write operations that can be performed on an object per second when the burst function is enabled.
        NOTE:
        • The burst function boosts the IOPS of an object within a specified period of time, temporarily improving object performance.
        • The system compares the effective maximum IOPS for an object with the burst IOPS. If the effective maximum IOPS is smaller, the burst function is enabled.
      • Burst duration: maximum duration when the actual IOPS of the controlled object reaches the burst IOPS.

      Max. MBPS/TB

      Maximum amount of data that can be transmitted on an object per second per TB.

      Max. MBPS

      Maximum amount of data that can be transmitted on an object per second.

      NOTE:
      • If the value of Max. MBPS/TB is greater than 0, calculate the effective maximum MBPS in the QoS policy as follows:
        1. Calculate (MBPS/TB x Object capacity) + 5.
        2. Compare the calculation result obtained in 1 with Max. MBPS. The smaller of the two values is the effective maximum MBPS.

        Suppose that Max. MBPS/TB is 20, object capacity is 2 TB, and Max. MBPS is 100. The effective maximum MBPS in the QoS policy is 45 (that is, 20 x 2 + 5), because 45 is smaller than 100.

      • If Max. MBPS/TB is set to 0, the effective maximum MBPS in the QoS policy is Max. MBPS.

      Burst MBPS/TB
      Maximum amount of data that can be transmitted on an object per second per TB when the burst function is enabled.
      NOTE:
      • The burst function boosts the amount of data that can be transmitted per second, temporarily improving object performance.
      • Total bandwidth triggered for an object = Burst MBPS/TB x Volume capacity
      • The system compares the effective maximum MBPS for an object with the total bandwidth triggered for the object. If the effective maximum MBPS is smaller, the burst function is enabled.
    • By read and write upper limits

      Table 2 describes related parameters.

      Table 2 Parameters of a QoS policy of the exclusive type

      Parameter

      Description

      Max. Read IOPS

      Maximum number of read operations that can be performed per second.

      Max. Write IOPS

      Maximum number of write operations that can be performed per second.

      Max. Read MBPS

      Maximum amount of data that can be read per second.

      Max. Write MBPS

      Maximum amount of data that can be written per second.

  6. Set basic parameters of a QoS policy of the shared type in either of the following ways, including By total performance upper limits and By read and write upper limits.

    • By total performance upper limits

      Table 3 describes related parameters.

      Table 3 Parameters of a QoS policy of the shared type

      Parameter

      Description

      Max. IOPS

      Maximum IOPS of the storage pool, that is, the maximum number of read/write operations that can be performed by the storage pool per second.

      Burst IOPS/Duration

      Maximum number of read/write operations that can be performed by the storage pool per second within a specified period when the burst function is enabled.

      Burst duration: maximum duration when the actual IOPS of the controlled object reaches the burst IOPS.
      NOTE:

      The burst function boosts the IOPS of an object within a specified period of time, temporarily improving object performance.

      Max. MBPS

      Maximum amount of data that can be transmitted by a storage pool per second.

      Burst MBPS/Duration

      Maximum amount of data that can be transmitted per second in the storage pool when the burst function is enabled.

      Burst duration: maximum duration when the actual MBPS of the controlled object reaches the burst MBPS.
      NOTE:

      The burst function boosts the amount of data that can be transmitted for an object per second within a certain period of time when high performance is required.
    • By read and write upper limits

      Table 4 describes related parameters.

      Table 4 Parameters of a QoS policy of the shared type

      Parameter

      Description

      Max. Read IOPS

      Maximum number of read operations that can be performed per second.

      Max. Write IOPS

      Maximum number of write operations that can be performed per second.

      Max. Read MBPS

      Maximum amount of data that can be read per second.

      Max. Write MBPS

      Maximum amount of data that can be written per second.

  7. Set a trigger policy for the QoS policy. Possible options are One-off, Daily, Weekly, and Always.

    • One-off: The QoS policy takes effect once at the specified time.
      1. In Start Date, set the date when the policy takes effect.
      2. In Start Time, set the time when the policy takes effect.
      3. In Duration, set the duration over which the policy remains in effect.

        The duration ranges from 30 minutes to 24 hours.

    • Daily: The QoS policy takes effect daily.
      1. In Start Date, set the date when the policy takes effect.
      2. In Start Time, set the time when the policy takes effect every day.
      3. In Duration, set the duration over which the policy remains in effect.

        The duration ranges from 30 minutes to 24 hours.

    • Weekly: The QoS policy takes effect weekly.
      1. In Start Date, set the date when the policy takes effect and the day when the policy takes effect every week.
      2. In Start Time, set the time when the policy takes effect every specified day of the week.
      3. In Duration, set the duration over which the policy remains in effect.

        The duration ranges from 30 minutes to 24 hours.

    • Always: The QoS policy remains in effect permanently.

  8. Specify objects for the QoS policy.

    • QoS policy of the exclusive type:
      • Volume
        1. Select the storage pool to which desired volumes belong.
        2. In the Available Volumes area, select one or more volumes. They will be automatically added to the Selected Volumes area on the right.
      • Snapshot
        1. Select the storage pool to which desired snapshots belong.
        2. In the Available Snapshots area, select one or more snapshots. They will be automatically added to the Selected Snapshots area on the right.
      • Storage pool

        In the Available Storage Pools area, select one or more storage pools. They will be automatically added to the Selected Storage Pools area on the right.

        • If different QoS policies are configured for a volume and its owning storage pool, the QoS policy configured for the volume takes effect.
        • If the object of a QoS policy is a storage pool, the system configures the SmartQoS policy for each volume or snapshot in the storage pool. For example, if Max. IOPS of the selected SmartQoS policy is set to 1000 and you add object storage pool StoragePool001, Max. IOPS of each volume or snapshot in the storage pool is 1000.
    • QoS policy of the shared type:
      • Storage pool

        In the Available Storage Pools area, select one or more storage pools. They will be automatically added to the Selected Storage Pools area on the right.

        For example, if Max. IOPS of the selected SmartQoS policy is set to 10,000 and you add object storage pool StoragePool001, Max. IOPS (total performance) of the storage pool does not exceed 10,000.

  9. Click OK.
  10. Confirm your operation as prompted.
Parent topic: Configuring and Managing SmartQoS Policies of the Block Service