Method for processing client requests in a cluster system, a method and an apparatus for processing i/o according to the client requests

A method for processing client request executed in a cluster system including a plurality of nodes, the method comprising:

• tagging a request identifier to the client request in accordance with a processing order of the client request in response to receiving the client request;
• forwarding a first sub-request derived from the client request to a first node of the plurality of nodes, and forwarding a second sub-request derived from the client request to a second node of the plurality of nodes, the request identifier being tagged to each of the first sub-request and the second sub-request;
• processing a first I/O request generated in accordance with the first sub-request, depending on the processing order of the request identifier tagged to the first sub-request, at the first node;
• and
• processing a second I/O request generated in accordance with the second sub-request, depending on the processing order of the request identifier tagged to the second sub-request, at the second node.

An apparatus for processing I/O, comprising:

• a hardware processor;
• a memory configured to load a computer program executed by the hardware processor;
• and
• a storage configured to store the computer program,
• wherein the computer program which, when executed by the hardware processor, causes the hardware processor to perform operations comprising
• receiving a first I/O request and a second I/O request, the first I/O request being classified as a critical I/O, and the second I/O request being classified as a non-critical I/O;
• assigning a priority higher than the second I/O request to the first I/O request;
• and
• processing the first I/O request and the second I/O request on the basis of the assigned priority,
• wherein the processing the first I/O request and the second I/O request comprises detecting that a processing state of the first I/O request is changed to a standby state by processing of the second I/O request, reclassifying the second I/O request as the critical I/O, and changing the priority of the second I/O request to the priority of the first I/O request in response to the detecting, and processing the second I/O request on the basis of the changed priority of the second I/O request.