Data transfer request processing scheme for reducing mechanical actions in data storage system

A data transfer request processing device for processing data transfer requests with respect to a storage device that requires mechanical actions in carrying out data transfers, comprising:

• an accepting unit configured to sequentially accept the data transfer requests;
• a time setting unit configured to set, if each accepted data transfer request is accompanied with a deadline for completing a requested data transfer, a time earlier than the deadline as a corresponding class switching time for the accompanied data transfer request;
• a classifying unit configured to repeatedly check whether a current time has exceeded the corresponding class switching time of each accepted data transfer request and to classify each accepted data transfer request into a first class when the current time has already exceeded the corresponding class switching time and to classify each accepted data transfer request into a second class when the current time has not yet exceeded the corresponding class switching time;
• a scheduling unit configured to schedule a processing of first class data transfer requests that are classified as the first class by the classifying unit according to a first scheduling policy in which a completion of data transfers requested by the data transfer requests within the deadlines specified for the data transfer requests is a primary key factor in determining an order of a processing, and to schedule a processing of second class data transfer requests that are classified as the second class by the classifying unit according to a second scheduling policy in which a reduction of amounts of the mechanical actions required in carrying out data transfers requested by the data transfer requests is a primary key factor in determining an order of processing;
• and
• a processing unit configured to process the data transfer requests according to a scheduling result obtained by the scheduling unit so as to control the storage device to carry out data transfers requested by the data transfer requests.

A computer usable medium having computer readable program codes embodied therein for causing a computer to function as a data transfer request processing device for processing data transfer requests with respect to a storage device that requires mechanical actions in carrying out data transfers, the computer readable program codes comprising:

• a first computer readable program code for causing said computer to sequentially accept the data transfer requests;
• a second computer readable program code for causing said computer to set, if each accepted data transfer request is accompanied with a deadline for completing a requested data transfer, a time earlier than the deadline as a corresponding class switching time for the accompanied data transfer request;
• a third computer readable program code for causing said computer to repeatedly check whether a current time has exceeded the corresponding class switching time of each accepted data transfer request and to classify each accepted data transfer request into a first class when the current time has already exceeded the corresponding class switching time and to classify each accepted data transfer request into a second class when the current time has not yet exceeded the corresponding class switching time;
• a fourth computer readable program code for causing said computer to schedule processing of first class data transfer requests that are classified as the first class by the third computer readable program code according to a first scheduling policy in which a completion of data transfers requested by the data transfer requests within the deadlines specified for the data transfer requests is a primary key factor in determining an order of processing, and to schedule processing of second class data transfer requests that are classified as the second class by the third computer readable program code according to a second scheduling policy in which a reduction of amounts of the mechanical actions required in carrying out data transfers requested by the data transfer requests is a primary key factor in determining an order of processing;
• and
• a fifth computer readable program code for causing said computer to process the data transfer requests according to a scheduling result obtained by the fourth computer readable program code so as to control the storage device to carry out data transfers requested by the data transfer requests.

A data storage system, comprising:

• a storage device that requires mechanical actions in carrying out data transfers;
• an accepting unit configured to sequentially accept the data transfer requests;
• a time setting unit configured to set, if each accepted data transfer request is accompanied with a deadline for completing a requested data transfer, a time earlier than the deadline as a corresponding class switching time for the accompanied data transfer request;
• a classifying unit configured to repeatedly check whether a current time has exceeded the corresponding class switching time of each accepted data transfer request and to classify each accepted data transfer request into a first class when the current time has already exceeded the corresponding class switching time and to classify each accepted data transfer request into a second class when the current time has not yet exceeded the corresponding class switching time;
• a scheduling unit configured to schedule a processing of first class data transfer requests that are classified as the first class by the classifying unit according to a first scheduling policy in which a completion of data transfers requested by the data transfer requests within the deadlines specified for the data transfer requests is a primary key factor in determining an order of processing, and to schedule a processing of second class data transfer requests that are classified as the second class by the classifying unit according to a second scheduling policy in which a reduction of amounts of the mechanical actions required in carrying out data transfers requested by the data transfer requests is a primary key factor in determining an order of processing;
• and
• a processing unit configured to process the data transfer requests according to a scheduling result obtained by the scheduling unit so as to control the storage device to carry out data transfers requested by the data transfer requests.