Help Center/ Data Lake Insight/ User Guide/ Creating an Elastic Resource Pool and Queues Within It/ Managing Elastic Resource Pools/ Setting CUs
Updated on 2024-08-20 GMT+08:00
View PDF

Setting CUs

CU settings are used to control the maximum and minimum CU ranges for elastic resource pools to avoid unlimited resource scaling.

For example, an elastic resource pool has a maximum of 256 and two queues, and each queue must have at least 64 CUs. If you want to add another queue that needs at lest 256 CUs to the elastic resource pool, the operation is not allowed due to the maximum CUs of the elastic resource pool.

Precautions

  • In any time segment of a day, the total minimum CUs of all queues in an elastic resource pool cannot be more than the minimum CUs of the pool.
  • In any time segment of a day, the maximum CUs of any queue in an elastic resource pool cannot be more than the maximum CUs of the pool.
  • When you change the minimum CUs of a created elastic resource pool, ensure that the value is no more than the current CU value. Otherwise, the modification fails.

Setting CUs

  1. In the navigation pane on the left, choose Resources > Resource Pool.
  2. Locate the row that contains the desired elastic resource pool, click More in the Operation column, and select Set CUs.
  3. In the Set CUs dialog box, set the minimum CUs on the left and the maximum CUs on the right. Click OK.

What Are the Actual CUs, CU Range, and Specifications of an Elastic Resource Pool?

  • Actual CUs: number of CUs that can be allocated in the elastic resource pool.
  • CU range: CU settings are used to control the maximum and minimum CU ranges for elastic resource pools to avoid unlimited resource scaling.
    • The total minimum CUs of all queues in an elastic resource pool must be no more than the minimum CUs of the pool.
    • The maximum CUs of any queue in an elastic resource pool must be no more than the maximum CUs of the pool.
    • An elastic resource pool should at least ensure that all queues in it can run with the minimum CUs and should try to ensure that all queues in it can run with the maximum CUs.
  • Specifications: The minimum CUs selected during elastic resource pool purchase are elastic resource pool specifications. Specifications are specific to yearly/monthly elastic resource pools. The specifications are billed on a yearly/monthly basis, while the extra CUs are billed in pay-per-use mode.

How Do I Increase the Minimum Value of the CU Range?

The minimum value of the CU range of an elastic resource pool is less than or equal to the actual CUs of the elastic resource pool. To adjust the minimum value of the CU range to be greater than the current CUs, increase the actual CUs first.

The following operations apply when the number of target CUs is less than or equal to the maximum value of the CU range. If the number of target CUs is greater than the maximum value of the CU range, increase the maximum CUs of the elastic resource pool first.

  • For a yearly/monthly elastic resource pool, you can increase its actual CUs by adjusting the maximum CUs of queues in or adding queues to the elastic resource pool. Then, you can change its specifications to be greater than or equal to the target CUs. In this case, the actual CUs are equal to the CUs provided by the specifications. Then, adjust the minimum value of the CU range to be equal to the target CUs.
  • For a pay-per-use elastic resource pool, you can increase its actual CUs by adjusting the maximum CUs of queues in or adding queues to the elastic resource pool. Then, adjust the minimum value of the CU range to be equal to the target CUs.

Example

  • Example 1: For a yearly/monthly elastic resource pool, the number of actual CUs is 64, the CU range is from 64 to 96, the number of CUs provided by the specifications is 64, and the target CU range is from 80 to 96.

    Procedure

    1. You can increase the actual CUs of an elastic resource pool by adjusting the maximum CUs of queues in or adding queues to the elastic resource pool.

      When the total number of maximum CUs of queues in the elastic resource pool is greater than its actual CUs, scale-out is triggered for the elastic resource pool. Actual CUs after scale-out = min (Total number of maximum CUs of queues, Maximum value of the CU range)

    2. Change the specifications of the elastic resource pool to 80 CUs. After the change, the minimum value of the CU range is automatically changed to the number of CUs provided by the specifications.
  • Example 2: For a pay-per-use elastic resource pool, the number of actual CUs is 64, the CU range is from 64 to 96, and the target CU range is from 80 to 96.

    Procedure

    1. You can increase the actual CUs of an elastic resource pool by adjusting the maximum CUs of queues in or adding queues to the elastic resource pool.

      When the total number of maximum CUs of queues in the elastic resource pool is greater than its actual CUs, scale-out is triggered for the elastic resource pool. Actual CUs after scale-out = min (Total number of maximum CUs of queues, Maximum value of the CU range)

    2. Adjust the CU range to the target one (80 to 96).
  • The adjustment of the CU range, specifications change, and CU setting of an elastic resource pool take effect on the next hour.
  • The adjustment of the actual CUs of an elastic resource pool by adding queues takes effect immediately.

How Do I Decrease the Maximum Value of the CU Range?

The minimum value of the CU range of an elastic resource pool is less than or equal to the actual CUs of the elastic resource pool. To adjust the maximum value of the CU range to be less than the current CUs, decrease the actual CUs first.

  • For a yearly/monthly elastic resource pool, you can decrease its actual CUs by deceasing the maximum CUs of queues in or deleting queues from the elastic resource pool. Then, you can change its specifications to be less than or equal to the target CUs. In this case, the actual CUs are equal to the CUs provided by the specifications. Then, adjust the minimum value of the CU range to be equal to the target CUs.
  • For a pay-per-use elastic resource pool, you can decrease its actual CUs by adjusting the maximum CUs of queues in or deleting queues from the elastic resource pool. Then, adjust the minimum value of the CU range to be equal to the target CUs.

Example

  • Example 1: For a yearly/monthly elastic resource pool, the number of actual CUs is 96, the CU range is from 64 to 128, the number of CUs provided by the specifications is 96, and the target CU range is from 64 to 80.

    Procedure

    1. You can decrease the actual CUs of an elastic resource pool by deceasing the maximum CUs of queues in or deleting queues from the elastic resource pool.

      When the total number of maximum CUs of queues in the elastic resource pool is less than its actual CUs, scale-in is triggered for the elastic resource pool. Actual CUs after scale-in = min (Total number of maximum CUs of queues, Maximum value of the CU range)

    2. Change the specifications of the elastic resource pool to 80 CUs. After the change, the minimum value of the CU range is automatically changed to the number of CUs provided by the specifications.
  • Example 2: For a pay-per-use elastic resource pool, the number of actual CUs is 96, the CU range is from 64 to 128, and the target CU range is from 64 to 80.

    Procedure

    1. You can decrease the actual CUs of an elastic resource pool by deceasing the maximum CUs of queues in or deleting queues from the elastic resource pool.

      When the total number of maximum CUs of queues in the elastic resource pool is less than its actual CUs, scale-in is triggered for the elastic resource pool. Actual CUs after scale-in = min (Total number of maximum CUs of queues, Maximum value of the CU range)

    2. Adjust the CU range to the target one (64 to 80).
  • The adjustment of the CU range, specifications change, and CU setting of an elastic resource pool take effect on the next hour.
  • The adjustment of the actual CUs of an elastic resource pool by adding queues takes effect immediately.