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Assigning FlexShare priority to system operations relative to user operations

If system operations (for example, SnapMirror transfers or ndmpcopy operations) are negatively affecting the performance of user accesses to the storage system, you can use FlexShare to assign the priority of system operations to be lower than that of user operations for any volume.

About this task

Synchronous SnapMirror updates are not considered system operations because they are performed from NVRAM when the primary operation is initiated. Therefore, synchronous SnapMirror updates are affected by the volume priority of the target volume, but not by the relative priority of system operations for that volume.

Steps

  1. If you have not already done so, ensure that FlexShare is enabled for your storage system by entering the following command:
    priority on
  2. Specify the priority for system operations for the volume by entering the following command:
    priority set volume vol_name system=priority_level

    vol_name is the name of the volume for which you want to set the priority of system operations.

    priority_level is one of the following values:
    • VeryHigh
    • High
    • Medium (default)
    • Low
    • VeryLow
    • A number from 4 (VeryLow) to 96 (VeryHigh)

    For more information about the priority command, see the na_priority(1) man page.

    Example

    The following command sets the priority level for the dbvol volume as high as possible while setting system operations for that volume to 30.

    priority set volume dbvol level=VeryHigh system=30

    Note: Setting the priority of system operations to 30 does not mean that 30 percent of storage system resources are devoted to system operations. Rather, when both user and system operations are requested, the system operations will be selected over the user operations 30 percent of the time, and the other 70 percent of the time the user operation is selected.

  3. You can optionally verify the priority levels of the volume by entering the following command:
    priority show volume -v vol_name