Method for assuring quality of service in distributed storage system, control node, and system

A control node, comprising:

• an interface;
• and
• a processor coupled to the interface and configured to:
• obtain, based on a quantity of remaining input/output (I/O) requests of a target storage node in a unit time, a quantity of I/O requests required by a storage resource to reach a lower assurance limit in the unit time, and a quantity of I/O requests that need to be processed by the target storage node in the unit time, a lower limit quantity of I/O requests that can be processed by the target storage node for the storage resource in the unit time, wherein the target storage node is one of N storage nodes that provide the storage resource in a storage system, N is a positive integer;
• allocate a lower limit quantity of tokens that is of the storage resource on the target storage node and that is in the unit time to the storage resource based on the lower limit quantity of I/O requests that can be processed by the target storage node for the storage resource in the unit time;
• and
• send the lower limit quantity of tokens to the target storage node.

A storage system, comprising a control node and N storage nodes, wherein the control node is configured to:

• obtain, based on a quantity of remaining input/output (I/O) requests of a target storage node in a unit time, a quantity of I/O requests required by a storage resource to reach a lower assurance limit in the unit time, and a quantity of I/O requests that need to be processed by the target storage node in the unit time, a lower limit quantity of I/O requests that can be processed by the target storage node for the storage resource in the unit time, wherein the target storage node is one of N storage nodes that provide the storage resource in a storage system, N is a positive integer;
• allocate a lower limit quantity of tokens that is of the storage resource on the target storage node and that is in the unit time to the storage resource based on the lower limit quantity of I/O requests that can be processed by the target storage node for the storage resource in the unit time;
• and
• send the lower limit quantity of tokens to the target storage node.